Improve suggestion when using any as type

[siiptuo]

Description

Using any instead of Any is an easy mistake to make because "any" has been used as a type in docstrings, editors may highlight it as it's the name for the built-in function and at least TypeScript uses it as a keyword. Here are some examples of this mistake in real-world Python code.

For example, for the following code:

def a(b: any): pass

mypy currently outputs:

any.py:1: error: Function "builtins.any" is not valid as a type
any.py:1: note: Perhaps you need "Callable[...]" or a callback protocol?

I think that the given suggestion is misleading and could be improved. This pull request changes the output to:

any.py:1: error: Function "builtins.any" is not valid as a type
any.py:1: note: Perhaps you meant "Any" instead of "any"?

Test Plan

Added a unit test to verify the new output.

[JelleZijlstra]

Thanks, good idea!

[hauntsaninja]

Thanks, this is great! One nit: maybe the error message should suggest typing.Any? I could imagine some new user naively going any -> Any without the import.

Would you be interested in making a similar PR for callable? :-)

[siiptuo]

@hauntsaninja

Thanks, this is great! One nit: maybe the error message should suggest typing.Any? I could imagine some new user naively going any -> Any without the import.

Good idea! I've updated the output.

Would you be interested in making a similar PR for callable? :-)

I can open a similar PR after this one.

[github-actions]

According to mypy_primer, this change has no effect on the checked open source code. 🤖🎉

[hauntsaninja]

Thank you!