There's no standard extension for these files, so no ftdetect, but an
ftplugin called `fishprofile` is defined that sets up tabstop and
folding to make it easier to read/navigate these files.

When reading a fish profile file, run `:setf fishprofile` to turn on the
plugin.

Clean up the ftplugin a bit. Use the save_cpo pattern to ensure cpo is
set appropriately, and define a b:undo_ftplugin.

Change the b:match_words definition to match else/else if.