feat(commands): support Annotated[tp, converter] in prefix commands

[shiftinv]

Summary

Fixes #1422.
See https://disnake--1431.org.readthedocs.build/en/1431/ext/commands/commands.html#typing-annotated for a proper explanation :>

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 uv run nox -s lint
  • I have type-checked the code by running uv run nox -s 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, ...)

[read-the-docs-community]

Documentation build overview

📚 disnake | 🛠️ Build #30378746 | 📁 Comparing f333072 against latest (66e27d8)

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Show files changed (50 files in total): 📝 50 modified | ➕ 0 added | ➖ 0 deleted

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index.html	📝 modified
whats_new.html	📝 modified
api/abc.html	📝 modified
api/activities.html	📝 modified
api/app_commands.html	📝 modified
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ext/commands/commands.html	📝 modified
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ext/commands/api/converters.html	📝 modified
ext/commands/api/exceptions.html	📝 modified
ext/commands/api/help_commands.html	📝 modified
ext/commands/api/misc.html	📝 modified
ext/commands/api/prefix_commands.html	📝 modified

[onerandomusername]

looks good, but we should make sure we support typing_extensions Annotated as well. This can be done by implementing typing_extensions.get_type_hints.

[Enegg]

I'm wondering if it's a good idea to make converters the only use of Annotated (in the context of prefix commands)
If we intend to upkeep/expand on prefix commands, perhaps it could be useful to have something akin to commands.Param for them?

[shiftinv]

looks good, but we should make sure we support typing_extensions Annotated as well. This can be done by implementing typing_extensions.get_type_hints.

@onerandomusername typing_extensions.Annotated is a simple alias in 3.10+, I don't expect that to be necessary:

$ uv run -p 3.10 python
Python 3.10.12 (main, Aug 15 2025, 14:32:43) [GCC 11.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import typing, typing_extensions
>>> typing.Annotated is typing_extensions.Annotated
True

[shiftinv]

I'm wondering if it's a good idea to make converters the only use of Annotated (in the context of prefix commands) If we intend to upkeep/expand on prefix commands, perhaps it could be useful to have something akin to commands.Param for them?

@Enegg Yeah, it would be nice to have prefix/slash commands diverge less long-term. Not necessarily with some sort of hybrid command, but more so by just reusing internals more between the two command types