Add hint to comment in the ListeningPluginUser header

source/RobotAPI/libraries/armem/client/plugins/ListeningPluginUser.h

@@ -17,6 +17,8 @@ namespace armarx::armem::client::plugins
      * topic (`MemoryListenerInterface`).
      *
      * Derive from this plugin user class to receive memory update events.
+     * If your class already inherits from an ice interface, your ice interface might need to inherit from the
+     * MemoryListenerInterface to avoid errors.
      */
     class ListeningPluginUser :
         virtual public PluginUser,