Docs: link hash doc to `object.__hash__` doc

[OTheDev]

Documentation

A note in the documentation for the hash builtin writes

See __hash__ for details

__hash__ should include a link.

Linked PRs

• gh-101880: add link to object.__hash__() in hash() builtin documentation #101883
• [3.12] gh-101880: add link to object.__hash__() in hash() builtin documentation (GH-101883) #106546
• [3.11] gh-101880: add link to object.__hash__() in hash() builtin documentation (GH-101883) #106547