[commands] Add support for type statement and NewType

[bijij]

Summary

This PR adds support for typing.NewType and type statement type aliases.
Closes #9813

Checklist

• If code changes were made then they have been tested.
  • I have updated the documentation to reflect the changes.
• This PR fixes an issue.
• This PR adds something new (e.g. new method or parameters).
• This PR is a breaking change (e.g. methods or parameters removed/renamed)
• This PR is not a code change (e.g. documentation, README, ...)

[Rapptz]

Might be worth doing this for app_commands as well?

[bijij]

At least doing a quick test this seems to work out of the box since app_commands also relies on the code in utils, unless I'm missing something.

[Rapptz]

Oh my mistake. I noticed this is actually within utils. For some reason on first read I thought this was under commands.py.