Do it now since the future awful.popup and notification widget
also uses it.
The `load_ldoc.cmake` changes allow to include `.ldoc` blocks in
existing ldoc comments. Previously, it added some extra newlines
and an autogenerated comments saying the content below was imported.
The problem is that this prevented the system to be used for shared
function arguments.
This commit also renames the `wibar` argument table from `arg` to
`args` as the name has to be the same in the `wibox` and `wibar`
constructor for this to work.
d99504775b