This should be the last commit that formats a big bunch of files. From
here on, whenever I merge patches, I’ll run clang-format like described
in the title.
open_input_window was slightly different for each of them, so it made no sense
to generalize it (then we would end up with a thin and useless wrapper).
Also, the API changed a bit. There are two functions now, both assume you
already got the keysyms (which is the case for i3 and i3-config-wizard),
one gets the modifier mapping for you (aio_get_mod_mask_for) while the other
assumes you also got that. No roundtrips are required for the latter.