add support for typed function parameters

[scottbelden]

Resolves #127

Please let me know what you think.

This should allow for typed parameters like def foo(x: int) and def foo(x: List[int]). I didn't try testing when parameters like *args or **kwargs are typed. I think that would be good to add in the future but it just wasn't as necessary for me at the moment.

This does not add support for typed variables or function return types, but I hope to add support for the later in the near future assuming this is accepted.

[scottbelden]

Also, when type annotations are present the type of the object is typed_name instead of name. In redbaron I would assumed TypedName would be a subclass of Name but I haven't looked over there yet to see if this makes sense.

[Psycojoker]

Hello,

Just to inform you that I've started looking at your PR, but it takes me /hours/ to correctly review most of the new grammar additions to baron (it's super sensible and I had quite some bad surprise) and this one is pretty complex.

If you haven't looked at it, this might helps you https://baron.readthedocs.io/en/latest/grammar.html#typed-arguments

Anyway, thanks a lot for this PR :)

[scottbelden]

Okay. Let me know if there is anything I can do to make the PR more bite size and easier to review.

[Psycojoker]

Finally merged (by hand so github don't detect that), thx again for your contribution :)

I end up adding more tests and finished all the cases (*a: int, **a: int), took me way more time to understand the grammar diff since there was a refactoring in python grammar in the middle of that for some reason.

[scottbelden]

Thanks!

[JosXa]

Hey awesome, I just stumbled over the problem and immediately I find out that there is a patch in the works on GitHub... nice work!