feat: allow passing autocompleters that take a cog as first argument to commands.Param

[Sharp-Eyes]

Summary

Currently, commands.Param assumes the provided autocompleter does not take a cog and is typehinted as such, despite somewhat working with alternative autocomplete options such as a simple sequence.

This PR ensures cog-based autocompleters work with commands.Param.
The typehint is changed to work with any valid autocompleter (callback without cog, callback with cog, sequence), and callbacks are internally marked so that slash commands handle them correctly.

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, ...)