fix(commands): Fix application command checks' typing

[elenakrittik]

Summary

This PR fixes typings related to application commands' checks (their addition/removal) and also implements commands.app_check and commands.app_check_any as an equivalent of commands.check and commands.check_any for application commands as making existing function type hint with application commands is near to impossible.

Fixes #1045

^{sorry for the .gitignore change}

Checklist

• If code changes were made, then they have been tested
  • I have updated the documentation to reflect the changes
  • I have formatted the code properly by running pdm lint
  • I have type-checked the code by running pdm pyright
• 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, ...)

[elenakrittik]

No idea why RTD build fails, but other than that this PR is ready.

[onerandomusername]

No idea why RTD build fails, but other than that this PR is ready.

Retriggering, might just be a quirk.

[shiftinv]

thanks!
The addition of app_check(_any) is a good idea, I don't see a way to make the existing decorator work with app commands either, especially in situations like @check(lambda inter: ...).

[elenakrittik]

Done.

[shiftinv]

Sorry for the long wait, finally got around to looking at this again.
The check_any decorator typing is still a bit iffy, but after spending some more time going down the rabbit hole of improving decorator typing more generally, it's out of scope for this PR.

[shiftinv]

lgtm, thanks! Finally getting rid of all those # type: ignores in cogs is a great change.