help(typing.Annotated[foo, ...]) should return the doc for _AnnotatedAlias

Split off from #89543; the module issue is fixed but other issues raised in the comments still remain valid. For the following code

>>> from typing import Annotated, Callable
>>> t = Annotated[int | str, "Some metadata"]
>>> help(t)
Help on _AnnotatedAlias in module typing:

Annotated = int | str

We should arguably ignore the instance and return the same thing as help(typing._AnnotatedAlias), analogously to help(int | str) returning the docs for Union

Linked PRs

• gh-97813

Commencez par le comportement reproduit de help(typing.Annotated[...]) et comparez-le à help(typing._AnnotatedAlias) et help(int | str). La modification est terminée lorsque l’instance de Annotated renvoie la documentation de _AnnotatedAlias au lieu de la sortie actuelle spécifique à l’instance.