elaborate on FbxPrefab fix

Author: vkovec

RELEASE_NOTES.md

@@ -8,7 +8,9 @@ NEW FEATURES
 
 FIXES
 
-* Fbx Prefab: handle FbxPrefab that is not the root of its prefab
+* Fbx Prefab: handle FbxPrefab that is not the root of its prefab. 
+
+Make a prefab instance. Parent it under a cube. Drag that to the project view (which creates a prefab). That used to not work, and upon update you'd lose your cube.
 
 **Version**: 0.0.14a