ps.sh: fix ps arguments to work for busybox
ps.sh: fix ps arguments to work for busybox

Use the format specifier 'ppid,args' instead of 'ppid command'. POSIX
allows either spaces or commas as separators, but busybox only allows
commas. Furthermore, 'args' is recognized by POSIX[0] while 'command' is
not. On implementations of ps that do recognize 'command', it is simply
an alias for 'args', e.g. Debian[1] and FreeBSD[2].

[0]: https://pubs.opengroup.org/onlinepubs/9699919799/utilities/ps.html
[1]: https://manpages.debian.org/bullseye/procps/ps.1.en.html
[2]: https://www.freebsd.org/cgi/man.cgi?query=ps

tmux-plugins/tmux-resurrect