functools.partial should use PEP612 ParamSpec (depends on #8708)

Currently, functools.partial's __call__ method takes *args: Any, **kwargs: Any and returns _T (a TypeVar for the return type of the callable the partial is wrapping). This is decent, but matching the parameter typing would make this more useful in more situations.

I can sort of see how to deal with this, although I'll admit I'm unsure how to make this generically work. I imagine you could probably deal with some number of Concatenates (maybe up to 5 or 10) to deal with most cases. It's possible fixing this requires another PEP to allow an arbitrary-length Concatenate-type pattern.

Related to https://github.com/python/mypy/issues/1484

Commencez par stdlib/functools.pyi autour de la ligne 75 et examinez les concepts ParamSpec et Concatenate de la PEP 612. Vérifiez la dépendance à l’issue #8708 et à l’issue mypy associée avant de déterminer si le typage demandé est exprimable. Le travail est terminé lorsque call de functools.partial conserve le typage des paramètres du callable encapsulé au lieu d’utiliser Any.