DEV: (cmds) update XREAD & XREADGROUP command pages

[dwdougherty]

This is a Redis 8.10 feature.

Add the MAXCOUNT and MAXSIZE optional arguments to the XREAD and XREADGROUP command pages.

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Note

Low Risk
Documentation and static SVG updates only; no runtime or application code changes.

Overview
Documents Redis 8.10 optional MAXCOUNT and MAXSIZE on XREAD and XREADGROUP, including front matter (arguments, syntax_fmt, history), optional-argument sections, and new “The MAXCOUNT and MAXSIZE options” prose with examples (cumulative caps vs per-stream COUNT, interaction when both are set, minimum one entry, oversized-entry behavior).

XREADGROUP also records CLAIM in history with since: 8.4.0 on that argument. Railroad SVGs for both commands are widened to show the new optional tokens. Minor formatting tweaks (e.g. COUNT in backticks).

^{Reviewed by Cursor Bugbot for commit 643679a. Bugbot is set up for automated code reviews on this repo. Configure here.}

[github-actions]

DOC-6749

[github-actions]

Staging links:
https://redis.io/docs/staging/DOC-6749/commands/xread
https://redis.io/docs/staging/DOC-6749/commands/xread/
https://redis.io/docs/staging/DOC-6749/commands/xreadgroup
https://redis.io/docs/staging/DOC-6749/commands/xreadgroup/

[jit-ci]

🛡️ Jit Security Scan Results

✅ No security findings were detected in this PR

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^{Security scan by Jit}

[andy-stark-redis]

LGTM

[dwdougherty]

Thank you, @andy-stark-redis!