systemctl: show reverse dependencies or before/after ordering

Also update completion scripts a bit.

shell-completion/bash/systemctl

@@ -70,7 +70,7 @@ _systemctl () {
         local i verb comps mode
 
         local -A OPTS=(
-               [STANDALONE]='--all -a --defaults --fail --ignore-dependencies --failed --force -f --full --global
+               [STANDALONE]='--all -a --reverse --after --before --defaults --fail --ignore-dependencies --failed --force -f --full --global
                              --help -h --no-ask-password --no-block --no-legend --no-pager --no-reload --no-wall
                              --quiet -q --privileged -P --system --user --version --runtime'
                       [ARG]='--host -H --kill-mode --kill-who --property -p --signal -s --type -t --root'
@@ -117,7 +117,7 @@ _systemctl () {
         fi
 
         local -A VERBS=(
-                [ALL_UNITS]='is-active is-failed is-enabled status show mask preset help'
+                [ALL_UNITS]='is-active is-failed is-enabled status show mask preset help list-dependencies'
             [ENABLED_UNITS]='disable'
            [DISABLED_UNITS]='enable'
         [REENABLABLE_UNITS]='reenable'