This is to make pasting literals easier.
When a user pastes something, we normally take it as-is.
The exception is when a single-quote is open, e.g. the current token
is
foo'bar
When something is pasted here, we escape single-quotes (`'`) and
backslashes (`\\`), so typing a `'` after it will turn it into a
literal token.
Fixes#967.
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.
