Sync classref with current source

classes/class_packedscene.rst

@@ -56,7 +56,16 @@ Description
 
 A simplified interface to a scene file. Provides access to operations and checks that can be performed on the scene resource itself.
 
-TODO: explain ownership, and that node does not need to own itself
+Can be used to save a node to a file. When saving, the node as well as all the node it owns get saved (see ``owner`` property on :ref:`Node<class_node>`). Note that the node doesn't need to own itself.
+
+Example of saving a node:
+
+::
+
+    var scene = PackedScene.new()
+    var result = scene.pack(child)
+    if result == OK:
+        ResourceSaver.save("res://path/name.scn", scene) // or user://...
 
 Member Function Description
 ---------------------------