Build and install docs

[dakeryas]

Restore documentation for zathura (manpages etc).

[dakeryas]

I don't understand why this fails at all. The error message is not explicit, is it?

[zegervdv]

I'm using the homebrew actions and one of the checks is a linter/formatted check.

There's a command somewhere to run those locally but can't find them immediately from my phone.

[dakeryas]

Right, since the change was tiny, I got lazy and wanted to edit and commit directly in the browser! That was a bad idea since there was an empty line not so empty with a trailling space! Should be fixed now!

[zegervdv]

Thanks for adding this!