MyPy not recognizing ParamSpec usage with Generic #11362

Bug Report

Some latest MRs intend to make ParamSpec ignored, but do not seem to cover the use case of ParamSpec with Generic

To Reproduce

from typing import Generic

from typing_extensions import ParamSpec

P = ParamSpec("P")


class Test(Generic[P]):
    pass

Expected Behavior

MyPy should detect no errors

Actual Behavior

error: Free type variable expected in Generic[...]

Your Environment

• Mypy version used: mypy 0.920+dev.9aaeef5f355509ef789dbcdca1f15793698a5960
• Mypy command-line flags: N/A
• Mypy configuration options from mypy.ini (and other config files): N/A
• Python version used: 3.8.5
• Operating system and version: OSX