Completely type undocumented aliases for `heap*_max` functions in `heapq`

[jonathandung]

I only see an incomplete annotation for heapq._heapify_max, an alias for heapq.heapify_max for backwards compatibility since 3.14 and an internal helper before, in the heapq stub, whereas similar helpers _heappop_max and _heapreplace_max already existed before 3.14, and _heappush_max and _heappushpop_max were added in 3.14, presumably for consistency. All of the above are not mentioned in heapq.pyi. Since _heapify_max, technically undocumented, is already there, I see no reason to omit the others.

[JelleZijlstra]

We generally only add private objects if a user asks for one because they use it. Adding one does not create a precedent for adding others.

[jonathandung]

Fair. Should I revert the relevant changes in #15669?