Fix 'string length: Unknown option': add `--` before $subcommand
Fix count $subcommand always = 1 with `sudo` and `doas`:
give argv as array to __fish_complete_subcommand
[ci skip]
This was treated as a glob where it was still enabled, most likely removing the "-E" option from argparse,
which caused `sudo -E` to not be parsed correctly, breaking completion.
(There was no error because the glob was used with `set`)
Fixes#5675.
[ci skip]
__fish_complete_subcommand
* sudo:
- now can be completed bu group and user (-u and -g keys).
- subcommand completion is fixed
* __fish_complete_proc.fish is added to complete killall command with
list of running processes
* __fish_complete_tex.fish is updated with common options
* __fish_make_completion_signals.fish is added to make a list of kill
signals for kill and killall
* completions:
- minor filetype completions are added for djview, xpdf, mupdf, gv,
xdvi
- adduser is copmleted by user and group
- dlocate and dpkg are completed by packages
- find: -executable options is added
- htop: options
- funced and funcsave are completed by function names
- ifdown and ifup are copmleted by interfaces
- kill and killall: options, signals and processes
- latexmk, ln, nm: options
- lualatex and xelatex copmletions
- sudo: -u and -g options
- wvdial: presets
