Type annotate cli.progress_bars

[McSinyx]

This is mainly to set out examples for annotations of args and kwargs to avoid future confusions.

@deveshks, I'd be grateful if you can take a quick look at this before the maintainers starts there reviews, just to sandbox trivial mistakes, if any.

[deveshks]

Hi @McSinyx

I also have a PR for this (#7932) but I think it targets some other portions of this file.

Perhaps if you want to, you can tackle the issues I faced as per this comment by @pradyunsg #7932 (review) in this PR as well?

[McSinyx]

@deveshks, thank you for the heads-up! I'm still looking for the way to solve it. I'll mark this PR is draft for now then.

[McSinyx]

Closing in favor of GH-7932, since the change here is too trivial and the idea has been communicated.

Edit: Based on Python MRO, the mixins should be listed in the following order:

class BaseDownloadProgressBar(DownloadProgressMixin, InterruptibleMixin,
                              WindowsMixin):

As discussed in python/mypy#5837, the current issues with type annotation of mix methods involving elements defined in a non-base class can be solve by moving the classes in here to the front of the inheritance list. However, it is not possible without heavy refactoring, thus I suggest to wait for python/typing#246 to be implemented.