XPrivacyLua: add NonFreeAdd and adapt description

Closes: fdroid/fdroiddata#1191

metadata/eu.faircode.xlua.yml

@@ -1,3 +1,5 @@
+AntiFeatures:
+  - NonFreeAdd
 Categories:
   - System
   - Security
@@ -23,7 +25,7 @@ Description: |-
 
     * Simple to use
     * Manage any user or system app
-    * Extensible
+    * Extensible (only with proprietary "Pro Companion App")
     * Multi-user support
     * Free and open source
 
@@ -59,8 +61,8 @@ Description: |-
     * Hide: return empty list
     * Fake: return empty or fake value
 
-    It is possible to add custom restriction definitions, see this
-    [https://github.com/M66B/XPrivacyLua/blob/master/FAQ.md#FAQ8 FAQ] for details.
+    When using the proprietary "Pro Companion App" it is possible to add custom restriction definitions
+    See this [https://github.com/M66B/XPrivacyLua/blob/master/FAQ.md#FAQ8 FAQ] for details.
 
     '''Notes:'''