We keep __fish_is_nth_token for compatibility and edit the
implementations of __fish_is_nth_token, __fish_is_first_token and
__fish_is_token_n to use fish_is_nth_token
New fish_indent does that too, so this will make any future reformatting
diffs smaller.
Done using either of:
perl -pi -e 'undef $/; s/\n*$/\n/' share/**.fish
kak -n -f '<a-/>\n*<ret>d' share/**.fish
