Mention that Node's `owner` must be set for persistence to work

This is already done in `Node.add_child()` documentation, but
this copies the note in `Node.owner` for good measure.

(cherry picked from commit be1acf3b92b8b7104fe4d1fab9fbd2a28400ff95)

doc/classes/Node.xml

@@ -118,7 +118,7 @@
 				    child_node.get_parent().remove_child(child_node)
 				add_child(child_node)
 				[/codeblock]
-				[b]Note:[/b] If you want a child to be persisted to a [PackedScene], you must set [member owner] in addition to calling [method add_child]. This is typically relevant for [url=https://godot.readthedocs.io/en/3.2/tutorials/misc/running_code_in_the_editor.html]tool scripts[/url] and [url=https://godot.readthedocs.io/en/latest/tutorials/plugins/editor/index.html]editor plugins[/url]. If [method add_child] is called without setting [member owner], the newly added [Node] will not be visible in the scene tree, though it will be visible in the 2D/3D view.
+				[b]Note:[/b] If you want a child to be persisted to a [PackedScene], you must set [member owner] in addition to calling [method add_child]. This is typically relevant for [url=$DOCS_URL/tutorials/misc/running_code_in_the_editor.html]tool scripts[/url] and [url=$DOCS_URL/tutorials/plugins/editor/index.html]editor plugins[/url]. If [method add_child] is called without setting [member owner], the newly added [Node] will not be visible in the scene tree, though it will be visible in the 2D/3D view.
 			</description>
 		</method>
 		<method name="add_child_below_node">
@@ -741,6 +741,7 @@
 		</member>
 		<member name="owner" type="Node" setter="set_owner" getter="get_owner">
 			The node owner. A node can have any other node as owner (as long as it is a valid parent, grandparent, etc. ascending in the tree). When saving a node (using [PackedScene]), all the nodes it owns will be saved with it. This allows for the creation of complex [SceneTree]s, with instancing and subinstancing.
+			[b]Note:[/b] If you want a child to be persisted to a [PackedScene], you must set [member owner] in addition to calling [method add_child]. This is typically relevant for [url=$DOCS_URL/tutorials/misc/running_code_in_the_editor.html]tool scripts[/url] and [url=$DOCS_URL/tutorials/plugins/editor/index.html]editor plugins[/url]. If [method add_child] is called without setting [member owner], the newly added [Node] will not be visible in the scene tree, though it will be visible in the 2D/3D view.
 		</member>
 		<member name="pause_mode" type="int" setter="set_pause_mode" getter="get_pause_mode" enum="Node.PauseMode" default="0">
 			Pause mode. How the node will behave if the [SceneTree] is paused.