Link from typing docs to specific sections in the typing spec

The typing docs currently frequently link to the PEPs that defined new typing features. Instead, they should link to the typing spec, which unlike the PEPs is a living document.

In the online documentation, we can do this with intersphinx. I have this running locally and can send a PR.

I'm less sure about how to handle this in the docstrings. For example, Protocol's docstring refers to PEP 544: https://github.com/python/cpython/blob/b32789ccb91bbe43e88193f68b1364a8da6d9866/Lib/typing.py#L1987. Should we provide a full URL to the spec, like https://typing.readthedocs.io/en/latest/spec/protocol.html?

Linked PRs

• gh-117540

Comece revisando os links da documentação de typing e a configuração do intersphinx; em seguida, inspecione a docstring de Protocol em Lib/typing.py ao redor do link referenciado para PEP 544. Decida como tanto a documentação online quanto as docstrings devem apontar para a especificação atual de typing e verifique se os links relevantes usam as seções pretendidas da especificação.