Bugs/improvement in typing

[henryiii]

This is a place to discuss issues in typing, or things that could be improved.

[henryiii]

NumPy does not specialize dtype.names based on the argument to dtype[...], but I think it could. Some dtypes will not return None for names. (Idea for NumPy contribution)

[henryiii]

NumPy does not include a Protocol for _SupportsUFunc, but it probably should. The definition of _SupportsArray is not ideal, too, but that's fixed in 1.21. (Idea for NumPy contribution)