[tkinter] Remove _WhatToCount alias

[donbarbos]

No description provided.

[github-actions]

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

[Akuli]

I suspect this won't actually make things better for IDE users. Can someone using vscode try this and show a screenshot of how the signature appears?

(I'm asking about vscode specifically for two reasons: it is used a lot with Python, and people usually program with tkinter before they are advanced enough to dislike vscode for one reason or another.)

[Avasam]

@Akuli Using Pylance as the language server (I specify because ty will actually be a thing very soon):

Before:

This PR:

As I would expect, it changes the rendered signature but autocomplete stays the same.

My opinion: Such aliases aren't meant for user visibility as much as they are to avoid repeating very large unions in stubs and/or to keep them in sync (or even establish a relationship between multiple params/attributes in that they all follow the same expected types)

[Akuli]

I see: the usability improves much less than I expected, and the error messages are somewhat messy in any case. So IMO this is not worth doing.

@donbarbos: Thanks for working on this, even though I chose not to merge.