A way to relax param-spec -- AnyLike

What what i would really like is https://github.com/python/typing/issues/1506
however mapping types is pretty complex and general.

Consider something like Dask's client.submit
submit[T, **P](self, func: Callable[P, T], *args: P.args, **kwargs: P.kwargs) -> Future[T]
What it actually wants is any type in the outer arguments can be
either the original type Q, in P.args or P.kwargs, or Future[Q].

But specifying that is a bit fiddly.

A less complex thing would be to introduce a special form AnyLike
which can be run as

submit[T, **P](self, func: Callable[P, T], *args: AnyLike[P].args, **kwargs: AnyLike[P].kwargs) -> Future[T]
which would have the effect of allowing the types in
args to be Any but the number must match that in the paramspec P,
and similar the types in kwargs can be Any but the names must till match those in the paramspec P

首先阅读 typing issue 1506 以及针对 Dask 的 client.submit 提出的 AnyLike 用法。定义 P.args 和 P.kwargs 的预期语义，包括参数数量和关键字名称，并考虑该提案如何适配现有的 ParamSpec 行为；当就新的 special form 达成一致的规范时，即视为完成。