docs: Docs-wide link fixes and xref update (#4102)

* Docs-wide link fixes and xref update

* Typo in API docs

Author: jabbacakes

com.unity.netcode.gameobjects/Documentation~/advanced-topics/custom-serialization.md

@@ -68,4 +68,4 @@ Reading and writing a value provides the minimal amount of `NetworkVariable` fun
 
 Here is a full implementation of a custom type with the methods needed for `UserNetworkVariableSerialization`
 
-[!code-cs[](../../Tests/Runtime/DocumentationCodeSamples/NetworkVariable/NetworkVariableSerialization.cs#HealthExample)]
+[!code-cs[](../../Tests/Runtime/DocumentationCodeSamples/NetworkVariable/CustomSerializationDocsTests.cs#HealthExample)]

com.unity.netcode.gameobjects/Documentation~/advanced-topics/fastbufferwriter-fastbufferreader.md

@@ -82,7 +82,7 @@ This allows the four bytes of the embedded struct to be rapidly serialized as a
 
 `FastBufferWriter` and `FastBufferReader` are replacements for the old `NetworkWriter` and `NetworkReader`. For those familiar with the old classes, there are some key differences:
 
-- `FastBufferWriter` uses `WriteValue()` as the name of the method for all types *except* [`INetworkSerializable`](serialization/inetworkserializable) types, which are serialized through `WriteNetworkSerializable()`
+- `FastBufferWriter` uses `WriteValue()` as the name of the method for all types *except* [`INetworkSerializable`](serialization/inetworkserializable.md) types, which are serialized through `WriteNetworkSerializable()`
 - `FastBufferReader` similarly uses `ReadValue()` for all types except INetworkSerializable (which is read through `ReadNetworkSerializable`), with the output changed from a return value to an `out` parameter to allow for method overload resolution to pick the correct value.
 - `FastBufferWriter` and `FastBufferReader` outsource packed writes and reads to `BytePacker` and `ByteUnpacker`, respectively.
 - `FastBufferWriter` and `FastBufferReader` are **structs**, not **classes**. This means they can be constructed and destructed without GC allocations.

com.unity.netcode.gameobjects/Documentation~/advanced-topics/message-system/rpc-params.md

@@ -75,7 +75,7 @@ void AbcdServerRpc(int somenumber) { /* ... */ }
 void XyzwServerRpc(int somenumber, ServerRpcParams serverRpcParams = default) { /* ... */ }
 ```
 
-[ServerRpcParams Documentation](https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@latest?subfolder=/api/Unity.Netcode.ServerRpcParams.html)
+[ServerRpcParams Documentation](xref:Unity.Netcode.ServerRpcParams)
 
 ## ClientRpc Params
 
@@ -94,7 +94,7 @@ void AbcdClientRpc(int framekey) { /* ... */ }
 void XyzwClientRpc(int framekey, ClientRpcParams clientRpcParams = default) { /* ... */ }
 ```
 
-[ClientRpcParams Documentation](https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@latest?subfolder=/api/Unity.Netcode.ClientRpcParams.html)
+[ClientRpcParams Documentation](xref:Unity.Netcode.ClientRpcParams)
 
 > [!NOTE]
 > `ClientRpcSendParams`'s `TargetClientIds` property is a `ulong[]` which means everytime you try to specify a subset of target clients or even a single client target, you will have to allocate a `new ulong[]`. This pattern can quickly lead into lots of heap allocations and pressure GC which would cause GC spikes at runtime. We suggest developers cache their `ulong[]` variables or use an array pool to cycle `ulong[]` instances so that it would cause less heap allocations.

com.unity.netcode.gameobjects/Documentation~/advanced-topics/message-system/rpc.md

@@ -328,4 +328,4 @@ void Update()
 ## Additional resources
 
 * [RPC parameters](rpc-params.md)
-* [Customizing serialization](../custom-serialization.md#remote-procedure-call-rpc)
+* [Customizing serialization](../custom-serialization.md#remote-procedure-call-rpcs)

com.unity.netcode.gameobjects/Documentation~/advanced-topics/network-prefab-handler.md

@@ -2,7 +2,7 @@
 
 The network prefab handler system provides advanced control over how network prefabs are instantiated and destroyed during runtime. You can use it to override the default Netcode for GameObjects [object spawning](../basics/object-spawning.md) behavior by implementing custom prefab handlers.
 
-The network prefab handler system is accessible from the [NetworkManager](../components/networkmanager.md) as `NetworkManager.PrefabHandler`.
+The network prefab handler system is accessible from the [NetworkManager](../components/core/networkmanager.md) as `NetworkManager.PrefabHandler`.
 
 ## When to use a prefab handler
 
@@ -13,14 +13,14 @@ For an overview of the default object spawning behavior, refer to the [object sp
 - **Custom initialization**: Setting up objects with game client specific data or configurations.
 - **Conditional spawning**: Initializing different prefab variants based on runtime conditions.
 
-The prefab handler system addresses these needs through an interface-based architecture. The system relies on two key methods: `Instantiate` and `Destroy`. `Instantiate` is called on non-authority clients when an [authority](../terms-concepts/authority.md) spawns a new [NetworkObject](../basics/networkobject.md) that has a registered network prefab handler. `Destroy` is called on all game clients whenever a registered [NetworkObject](../basics/networkobject.md) is destroyed.
+The prefab handler system addresses these needs through an interface-based architecture. The system relies on two key methods: `Instantiate` and `Destroy`. `Instantiate` is called on non-authority clients when an [authority](../terms-concepts/authority.md) spawns a new [NetworkObject](../components/core/networkobject.md) that has a registered network prefab handler. `Destroy` is called on all game clients whenever a registered [NetworkObject](../components/core/networkobject.md) is destroyed.
 
 ## Create a prefab handler
 
 Prefab handlers are classes that implement one of the Netcode for GameObjects prefab handler descriptions. There are currently two such descriptions:
 
-- [**INetworkPrefabInstanceHandler**](https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@latest?subfolder=/api/Unity.Netcode.INetworkPrefabInstanceHandler.html): This is the simplest interface for custom prefab handlers.
-- [**NetworkPrefabInstanceHandlerWithData**](https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@latest?subfolder=/api/Unity.Netcode.NetworkPrefabInstanceHandlerWithData.html): This specialized handler receives custom data from the authority during spawning, enabling dynamic prefab customization.
+- [**INetworkPrefabInstanceHandler**](xref:Unity.Netcode.INetworkPrefabInstanceHandler): This is the simplest interface for custom prefab handlers.
+- [**NetworkPrefabInstanceHandlerWithData**](xref:Unity.Netcode.NetworkPrefabInstanceHandlerWithData): This specialized handler receives custom data from the authority during spawning, enabling dynamic prefab customization.
 
 When using a prefab handler, Netcode for GameObjects uses the `Instantiate` and `Destroy` methods instead of default spawn handlers for the NetworkObject during spawning and despawning. The authority instance uses the traditional spawning approach where it will, via user script, instantiate and spawn a network prefab (even for those registered with a prefab handler). However, all non-authority clients will automatically use the instantiate method defined by the `INetworkPrefabInstanceHandler` implementation if the network prefab spawned has a registered `INetworkPrefabInstanceHandler` implementation with the `NetworkPrefabHandler` (`NetworkManager.PrefabHandler`).
 
@@ -55,7 +55,7 @@ public abstract class NetworkPrefabInstanceHandlerWithData<T> : INetworkPrefabIn
 
 ## Register a prefab handler
 
-Once you've [created a prefab handler](#create-a-prefab-handler), whether by implementing or deriving, you need to register any new instance of that handler with the network prefab handler system using `NetworkManager.PrefabHandler.AddHandler`. Prefab handlers are registered against a NetworkObject's [GlobalObjectIdHash](../basics/networkobject.md#using-networkobjects).
+Once you've [created a prefab handler](#create-a-prefab-handler), whether by implementing or deriving, you need to register any new instance of that handler with the network prefab handler system using `NetworkManager.PrefabHandler.AddHandler`. Prefab handlers are registered against a NetworkObject's [GlobalObjectIdHash](../components/core/networkobject.md#using-networkobjects).
 
 ```csharp
 public class GameManager : NetworkBehaviour
@@ -70,7 +70,7 @@ public class GameManager : NetworkBehaviour
 }
 ```
 
-To un-register a prefab handler, you can [invoke the `NetworkManager.PrefabHandler.RemoveHandler` method](https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@latest?subfolder=/api/Unity.Netcode.NetworkPrefabHandler.html#Unity_Netcode_NetworkPrefabHandler_RemoveHandler_System_UInt32_). There are several override versions of this method.
+To un-register a prefab handler, you can [invoke the `NetworkManager.PrefabHandler.RemoveHandler` method](xref:Unity.Netcode.NetworkPrefabHandler.RemoveHandler*). There are several override versions of this method.
 
 ## Object spawning with prefab handlers
 

com.unity.netcode.gameobjects/Documentation~/advanced-topics/network-update-loop-system/network-update-loop-reference.md

@@ -6,14 +6,14 @@ The following diagrams provide insight into the Network Update Loop process and
 
 <div class="imgwhite">
 
-![Injecting NetworkUpdateLoop Systems Into PlayerLoop](../images/injecting-networkupdatesloop.svg)
+![Injecting NetworkUpdateLoop Systems Into PlayerLoop](../../images/injecting-networkupdatesloop.svg)
 
 </div>
 
 ## NetworkUpdateLoop Running INetworkUpdateSystem Updates
 
 <div class="imgwhite">
 
-![NetworkUpdateLoop Running INetworkUpdateSystem Updates](../images/runninginetworkupdatesystemupdates.svg)
+![NetworkUpdateLoop Running INetworkUpdateSystem Updates](../../images/runninginetworkupdatesystemupdates.svg)
 
 </div>

com.unity.netcode.gameobjects/Documentation~/advanced-topics/networkobject-parenting.md

@@ -26,7 +26,7 @@ If you aren't familiar with transform parenting in Unity, then it's recommended
 
 ### OnNetworkObjectParentChanged
 
-[`NetworkBehaviour.OnNetworkObjectParentChanged`](https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@latest?subfolder=/api/Unity.Netcode.NetworkBehaviour.html#Unity_Netcode_NetworkBehaviour_OnNetworkObjectParentChanged_Unity_Netcode_NetworkObject_) is a virtual method you can override to be notified when a NetworkObject component's parent has changed. The [`MonoBehaviour.OnTransformParentChanged()`](https://docs.unity3d.com/ScriptReference/MonoBehaviour.OnTransformParentChanged.html) method is used by NetworkObject component to catch `transform.parent` changes and notify its associated NetworkBehaviour components.
+[`NetworkBehaviour.OnNetworkObjectParentChanged`](xref:Unity.Netcode.NetworkBehaviour.OnNetworkObjectParentChanged*) is a virtual method you can override to be notified when a NetworkObject component's parent has changed. The [`MonoBehaviour.OnTransformParentChanged()`](https://docs.unity3d.com/ScriptReference/MonoBehaviour.OnTransformParentChanged.html) method is used by NetworkObject component to catch `transform.parent` changes and notify its associated NetworkBehaviour components.
 
 ```csharp
 /// <summary>
@@ -49,7 +49,7 @@ The [owner](../terms-concepts/ownership.md) of a NetworkObject can always parent
 
 By default, only the [authority](../terms-concepts/authority.md) of a NetworkObject can parent a NetworkObject under a non-networked object. This means in a client-server game, only the server (or host) can control NetworkObject component parenting. In a distributed authority game the [owner](../terms-concepts/ownership.md) of the object can always parent the object.
 
-To allow the [owner](../terms-concepts/ownership.md) to parent their owned NetworkObject in a client-server game, use the [`NetworkObject.AllowOwnerToParent`](https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@latest?subfolder=/api/Unity.Netcode.NetworkObject.html#Unity_Netcode_NetworkObject_AllowOwnerToParent) property.
+To allow the [owner](../terms-concepts/ownership.md) to parent their owned NetworkObject in a client-server game, use the [`NetworkObject.AllowOwnerToParent`](xref:Unity.Netcode.NetworkObject.AllowOwnerToParent) property.
 
 ![image](../images/networkobject/allowOwnerToParent.png)
 
@@ -78,7 +78,7 @@ If you plan on parenting in-scene placed NetworkObject components with a player
 For more information, refer to:
 
 - [Real World In-scene NetworkObject Parenting of Players Solution](inscene_parenting_player.md)
-- [Scene Event Notifications](../basics/scenemanagement/scene-events#scene-event-notifications)
+- [Scene Event Notifications](../basics/scenemanagement/scene-events.md#scene-event-notifications)
 - [In-Scene NetworkObjects](../basics/scenemanagement/inscene-placed-networkobjects.md)
 
 ### WorldPositionStays usage

com.unity.netcode.gameobjects/Documentation~/advanced-topics/networktime-ticks.md

@@ -183,6 +183,6 @@ For games with short play sessions casting the time to float is safe or `TimeAsF
 > [!NOTE]
 > The properties of the `NetworkTimeSystem` should be left untouched on the server/host. Changing the values on the client is sufficient to change the behavior of the time system.
 
-The way network time gets calculated can be configured in the `NetworkTimeSystem` if needed. Refer to the [API docs](https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@latest?subfolder=/api/Unity.Netcode.NetworkTimeSystem.html) for information about the properties which can be modified. All properties can be safely adjusted at runtime. For instance, buffer values can be increased for a player with a bad connection.
+The way network time gets calculated can be configured in the `NetworkTimeSystem` if needed. Refer to the [API docs](xref:Unity.Netcode.NetworkTimeSystem) for information about the properties which can be modified. All properties can be safely adjusted at runtime. For instance, buffer values can be increased for a player with a bad connection.
 
 <!-- On page code -->

com.unity.netcode.gameobjects/Documentation~/advanced-topics/physics.md

@@ -34,7 +34,7 @@ Since PhysX has no concept of local space, it can be difficult to synchronize tw
 
 ## Using AttachableBehaviour or Joint
 
-The implementation of physics in a networked project differs from a single player project. This is especially true when you're using NetworkTransform and NetworkRigidbody components with [`NetworkRigidbody.UseRigidBodyForMotion`](https://docs.unity3d.com/Packages/com.unity.netcode.gameobjects@latest?subfolder=/api/Unity.Netcode.Components.NetworkRigidbodyBase.html#Unity_Netcode_Components_NetworkRigidbodyBase_UseRigidBodyForMotion) enabled. Deciding whether to use a Joint or an AttachableBehaviour component depends on your project's requirements.
+The implementation of physics in a networked project differs from a single player project. This is especially true when you're using NetworkTransform and NetworkRigidbody components with [`NetworkRigidbody.UseRigidBodyForMotion`](xref:Unity.Netcode.Components.NetworkRigidbodyBase.UseRigidBodyForMotion) enabled. Deciding whether to use a Joint or an AttachableBehaviour component depends on your project's requirements.
 
 For example, if you want to create world items that players can pick up, you may have the following requirements:
 

com.unity.netcode.gameobjects/Documentation~/advanced-topics/serialization/inetworkserializable.md

@@ -1,7 +1,7 @@
 # Customize serializable types with INetworkSerializable
 
 > [!NOTE]
-> Read the [Serialization overview](./serialization/serialization-overview.md) page to understand the basics of serialization before customizing serializable types with `INetworkSerializable`.
+> Read the [Serialization overview](./serialization-overview.md) page to understand the basics of serialization before customizing serializable types with `INetworkSerializable`.
 
 You can use the `INetworkSerializable` interface to define custom serializable types. This interface has one function: `NetworkSerialize<T>(BufferSerializer<T> serializer)`, which ingests a bi-directional [`BufferSerializer`](../bufferserializer.md) that you can use to implement bi-directional custom serialization.
 
@@ -23,7 +23,7 @@ struct SpawnPoint : INetworkSerializable
 }
 ```
 
-Types implementing `INetworkSerializable` are supported by [`FastBufferReader` and `FastBufferWriter`](./fastbufferwriter-fastbufferreader.md), [`RPC`s'](../message-system/rpc.md), and [`NetworkVariable`s](../../basics/networkvariable.md).
+Types implementing `INetworkSerializable` are supported by [`FastBufferReader` and `FastBufferWriter`](../fastbufferwriter-fastbufferreader.md), [`RPC`s'](../message-system/rpc.md), and [`NetworkVariable`s](../../basics/networkvariable.md).
 
 ```csharp
 [Rpc(SendTo.Server)]