stdtypes don't mention asyncio generic classes

[asvetlov]

Documentation

https://docs.python.org/3/library/stdtypes.html#standard-generic-classes has a list of generic classes. Since ea5b968, asyncio provides generic Future and Task that are not mentioned.

Linked PRs

• gh-131417: Mention asyncio Future and Task in docs for generic classes list #131422

[JelleZijlstra]

Note the list explicitly says it's not exhaustive. I don't object to adding the asyncio ones but maybe we should trim down the list to builtin types instead.