For all other files leave the line width at 79 as before. This is a good idea
since we generally don't want text files such as catalog files, unit files or
README/NEWS files to be line-broken at 119 since they are regularly browsed on
text terminals.
While we are at it, also add a couple of comments to the various files.
(Note that .editorconfig doesn't carry line-width information, simply because
the specification doesn't know the concept.)
Let's be a bit more precise with the editor configuration and specify a higher fill column of 119. This isn't as emacs'
default of 70, but also not particularly high on today's screens.
While we are at it, also set a couple of other emacs C coding style variables.
