fix for `Argument of type "type[Command]" cannot be assigned to parameter "cls" of type "C@command" in function "command"`

[violet4]

Pull request summary

previously the typing of function twitchio.ext.command.core.command declared an argument cls: C = Command, but that was throwing a linting error (vscode pylance in my case) in any code that tried to create a command. it has been changed to cls: type[C] = Command.

demo code that showed the error before, and fixed after the change:

from twitchio.ext import commands

class MyBot(commands.Bot):

    # Argument of type "type[Command]" cannot be assigned to parameter "cls" of type "C@command" in function "command"
    # Type "type[Command]" cannot be assigned to type "Command"
    #     "type[type]" is incompatible with "type[Command]"PylancereportGeneralTypeIssues

    @commands.command(name="hello", aliases=['hi'])
    async def hello(self, ctx: commands.Context):
        await ctx.send(f'Hello {ctx.author.name}!')

Checklist

• [x] 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.
• [x] 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, ...)

[chillymosh]

Thanks