Add Description string to modules

[slotThe]

Description

Sigh.

Fixes: https://github.com/xmonad/xmonad-contrib/issues/592

Checklist

• [x] I've read CONTRIBUTING.md

• [x] I've considered how to best test these changes (property, unit, manually, ...) and concluded: It's docs

• [n/a] I updated the CHANGES.md file

• [n/a] I updated the XMonad.Doc.Extending file (if appropriate)

[slotThe]

Kudos! I'm curious, was this manual work?

Less than I was initially anticipating, actually. The work flow was basically as follows:

1. For every file that's in X.D.Extending, copy the first sentence in its description, find-file-at-point, insert a description after the Module keyword; this was done in a single macro and then looped over the file.
2. Build the Haddocks, find all modules that don't have descriptions (and are hence not in X.D.Extending), copy the names to a buffer, do essentially 1. again, only use the first line in the usage section; this also neatly fit into a macro.
3. Insert the modules that were missing into X.D.Extending; the format was macroable (using the usage section again for most modules), but inserting the modules into the right place was done manually because I couldn't think of a good way to script it (though it would probably be possible with a little bit more effort).
4. Fine-tuning—i.e., actually see whether the descriptions accurately describe the modules and are not too long for the Haddocks; this was manually because I get obsessive about that kind of stuff :)

[liskin]

Wow, thanks! :tada: