`@final` and `ParamSpec`

[sobolevn]

This code produces a strange error:

from typing import ParamSpec, Generic, final

_P = ParamSpec("_P")

@final  # E: Argument 1 to "final" has incompatible type "Type[_lru_cache_wrapper[Any]]"; expected "Type[_lru_cache_wrapper[Any]]"
class _lru_cache_wrapper(Generic[_P]):  
    pass

I will take a look, hopefully can fix it today.

Originally seen in python/typeshed#6986

[AlexWaygood]

The original error for this issue is no longer reproducible following @A5rocks's PR #11847. However, I'm not sure this issue should be closed yet, since @Akuli's PR #12096 may still be worth merging, as discussed in that PR thread and #11847 (comment)