[DUX-2822] Add --verbose, an alias for --log-filter ghciwatch=debug,info.

[a-02]

• Labeled the PR with patch, minor, or major to request a version bump when it's merged.
• Updated the user manual in docs/.
• Added integration / regression tests in tests/.

I don't work here anymore, but this is still bugging me. Is this close to what you were wanting?

[9999years]

Unfortunately the clap alias functionality is pretty limited -- it can only make add aliases for an existing argument (I doubt this works as written, but it would make ----log-filter ghciwatch=debug,info work the same as --verbose if it did).

The actual code won't be that much more complex, we just need to create some logic for figuring out the log filters and then use that. It'll look something like this:

https://github.com/home-mangler/home-mangler/blob/a9faf62e8ebe5ebbe1950daf2fef8ef6dd64eef4/src/cli.rs#L68-L86