feat: add proper typing support for bridge contexts

[AstreaTSS]

Summary

This PR adds a new function to BridgeContext and its two subclasses: typing(). In BridgeExtContext, this functions just like Context.typing, but in BridgeApplicationContext, this does a defer. This is most useful when you have a long running bridge command that lasts longer than what trigger_typing() allows.

An example (which showcases this better than any description could do) is below:

import asyncio
from discord.ext import bridge

bot = bridge.Bot(...)

@bot.bridge_command()
async def hello(ctx: bridge.Context):
    async with ctx.typing(ephemeral=True):
        await asyncio.sleep(15)
    await ctx.respond("Hello!")

This is a breaking change. ApplicationContext has a typing() function that types in the channel the command is being run, although the usefulness of this is debatable for slash commands; regardless, this overwrites that function.

Information

• 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, typehinting,
  examples, ...).

Checklist

• I have searched the open pull requests for duplicates.
• If code changes were made then they have been tested.
  • I have updated the documentation to reflect the changes.
• If type: ignore comments were used, a comment is also left explaining why.
• I have updated the changelog to include these changes.
• AI Usage has been disclosed.
  • If AI has been used, I understand fully what the code does

[pycord-app]

Thanks for opening this pull request!
Please make sure you have read the Contributing Guidelines and Code of Conduct.

This pull request can be checked-out with:

git fetch origin pull/3251/head:pr-3251
git checkout pr-3251

This pull request can be installed with:

pip install git+https://github.com/Pycord-Development/pycord@refs/pull/3251/head

[Paillat-dev]

lgtm although we should probably shift focus away from bridge and the exts for the time being until we conclude what to do with them

[Paillat-dev]

Why do we need both typing and _typing ?

[vmphase]

This is the template method pattern already used by respond, defer and others throughout the file.

[AstreaTSS]

(Actionable) reviews have been addressed! As for shifting focus, that's understandable. This was just meant to be a quick PR for a simple thing at the end of the day.