Update typing docstrings

[JelleZijlstra]

Bug report

Bug description:

I noticed a few outdated pieces of information in the docstrings in the typing module.

CPython versions tested on:

CPython main branch

Operating systems tested on:

No response

Linked PRs

• gh-149995: Update typing.py docstrings and documentation #149996
• [3.15] gh-149995: Update typing.py docstrings and documentation (GH-149996) #150215
• [3.14] gh-149995: Update typing.py docstrings and documentation #150216
• [3.13] gh-149995: Update typing.py docstrings and documentation #150217