Documentation indicates presence of removed `ast` members

[SnoopJ]

Documentation

The documentation for ast claims:

Old classes ast.Num, ast.Str, ast.Bytes, ast.NameConstant and ast.Ellipsis are still available, but they will be removed in future Python releases. In the meantime, instantiating them will return an instance of a different class.

These classes were removed in #119563 and are no longer available.

Linked PRs

• gh-137063: Remove notice about ast node types no longer available #137064

[picnixz]

The notice should be kept as it's under .. deprecated:: 3.8 however we should mention when they were removed with another note.