bash-completion: don't sort syslog priorities

By default, the available completions are sorted alphabetically, which
is counterproductive in case of syslog priorities. Override the default
behavior using the `nosort` option

shell-completion/bash/journalctl

@@ -83,6 +83,7 @@ _journalctl() {
                 ;;
             --priority|-p)
                 comps=${__syslog_priorities[*]}
+                compopt -o nosort
                 ;;
             --unit|-u)
                 comps=$(journalctl -F '_SYSTEMD_UNIT' 2>/dev/null)