Projucer: Improve the App Group ID setting help text

extras/Projucer/Source/ProjectSaving/jucer_ProjectExport_Xcode.h

@@ -671,7 +671,7 @@ public:
         if (iOS)
             props.add (new TextPropertyComponentWithEnablement (iosAppGroupsIDValue, iosAppGroupsValue, "App Group ID", 256, false),
                        "The App Group ID to be used for allowing multiple apps to access a shared resource folder. Multiple IDs can be "
-                       "added separated by a semicolon.");
+                       "added separated by a semicolon. The App Groups Capability setting must be enabled for this setting to have any effect.");
 
         props.add (new ChoicePropertyComponent (keepCustomXcodeSchemesValue, "Keep Custom Xcode Schemes"),
                    "Enable this to keep any Xcode schemes you have created for debugging or running, e.g. to launch a plug-in in"