Tab-autocomplete ruff config

[janosh]

Would be great if ruff config tab autocompletes:

ruff config is
# tab
ruff config isort

and

ruff config isort.spl
# tab
ruff config isort.split-on-trailing-comma

Related: #2808 hence pinging @not-my-profile

[MichalKacprzak99]

@charliermarsh Hi, I would like to work on this, can you assign it to me?

[charliermarsh]

You got it!

[dhruvmanila]

@MichalKacprzak99 Not in a hurry but just wondering if you've started working on this? Feel free to ask any questions if you're stuck :)

[hesampakdaman]

I looked at this issue a little bit during the weekend. I initially tried to create a derived macro for Options that creates an enum that I then implement clap::ValueEnum for. However, this approach is not viable because Rust doesn't support reflection, and I couldn't generate the enum variants for attributes #[option_group] recursively.

My only other idea is to create a huge enum by hand, but that would be a rather big code change.