feat: Add possibility to start bot via async context manager

[Snawe]

Summary

This is a feature pull request. It allowes you to start the bot via an async context manager.

Till now you were able to subclass Bot with something like

class MyBot(commands.Bot):
    def __init__(self, **kwargs: Any):
        super().__init__(
            **kwargs,
        )
        [...]

MyBot().run("token")

Now you can also start the bot via an async context manager

async with MyBot(**kwargs) as bot:
    await bot.start("token")

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.

[Lulalaby]

Thanks for the pull request!
We'll look into it by time.

[Snawe]

If you need something, leme know ;)

[codecov]

Codecov Report

Merging #1801 (8df12fc) into master (f553fde) will decrease coverage by 0.01%.
The diff coverage is 27.27%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1801      +/-   ##
==========================================
- Coverage   33.32%   33.32%   -0.01%     
==========================================
  Files          97       97              
  Lines       18916    18927      +11     
==========================================
+ Hits         6304     6307       +3     
- Misses      12612    12620       +8     

Flag	Coverage Δ
macos-latest-3.10	33.30% <27.27%> (-0.01%)	⬇️
macos-latest-3.11	33.30% <27.27%> (-0.01%)	⬇️
macos-latest-3.8	33.31% <27.27%> (-0.01%)	⬇️
macos-latest-3.9	33.31% <27.27%> (-0.01%)	⬇️
ubuntu-latest-3.10	33.30% <27.27%> (-0.01%)	⬇️
ubuntu-latest-3.11	33.30% <27.27%> (-0.01%)	⬇️
ubuntu-latest-3.8	33.31% <27.27%> (-0.01%)	⬇️
ubuntu-latest-3.9	33.31% <27.27%> (-0.01%)	⬇️
windows-latest-3.10	33.30% <27.27%> (-0.01%)	⬇️
windows-latest-3.11	33.30% <27.27%> (-0.01%)	⬇️
windows-latest-3.8	33.31% <27.27%> (-0.01%)	⬇️
windows-latest-3.9	33.31% <27.27%> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
discord/client.py	27.23% <27.27%> (+<0.01%)	⬆️

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[JustaSqu1d]

Please resolve merge conflicts.

[Snawe]

I did a rebase on master... but there were no conflicts. Not sure what you meant.

[Snawe]

Also, since this feature is done, it would be nice if you could remove the "in progress" label again ;)

[Snawe]

Any chance getting this merged? ;)

[BobDotCom]

Please add a changelog entry for this

[Dorukyum]

Could this be shown in the docs / basic examples?

[Snawe]

@BobDotCom changelog added
@Dorukyum basic example added

resolved