This removes a weird `ls` call (that just decorates directories), and
makes it behave like normal path completion.
(really, this should be a proper option to complete)
Fixes#9285
I hate doing this but I am tired of touching a fish script as part of
some change and having `make style` radically change it. Which makes
editing fish scripts more painful than it needs to be. It is time to do
a wholesale reformatting of these scripts to conform to the documented
style as implemented by the `fish_indent` program.