Description

Add support for custom command argument converters.

Example:

class LowerCaseConverter(commands.Converter[str]):

    async def convert(self, ctx: commands.Context, arg: str) -> str:
        return arg.lower()


@commands.command()
async def test(ctx: commands.Context, arg: LowerCaseConverter) -> None: ...

Checklist

• If code changes were made then they have been tested.
  • I have updated the documentation to reflect the changes.
  • I have updated the changelog with a quick recap of my 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, ...)
• I have read and agree to the Developer Certificate of Origin for this contribution