fix typing of various AppCommand decorators

[mikeshardmind]

Summary

Adds some overloads, fixes a couple erroneous return types on decorators which were not designed to be used as both @name and @name()

was briefly brought up in discord here: https://discord.com/channels/336642139381301249/1219651927113994291/1237362470511841310

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, ...)