feat(ip): Complete help for unknown subcommands

Author: yedayak

completions/ip

@@ -451,7 +451,7 @@ _comp_cmd_ip()
                     fi
                     ;;
                 *)
-                    _comp_compgen -- -W 'show'
+                    ((cword == subcword)) && _comp_compgen -- -W 'help show'
                     ;;
             esac
             ;;
@@ -463,10 +463,14 @@ _comp_cmd_ip()
                     ;;
                 *)
                     ((cword == subcword)) &&
-                        _comp_compgen -- -W 'state policy monitor'
+                        _comp_compgen -- -W 'help state policy monitor'
                     ;;
             esac
             ;;
+        help) ;;
+        *)
+            _comp_compgen -- -W 'help'
+            ;;
     esac
 } &&
     complete -F _comp_cmd_ip ip