Tree::get_edited Fix in docs example code

(cherry picked from commit b0bcbcc094)

doc/classes/Tree.xml

@@ -99,7 +99,7 @@
 				Returns the currently edited item. Can be used with [signal item_edited] to get the item that was modified.
 				[codeblock]
 				func _ready():
-				    $Tree.item_edited.connect(on_Tree_item_edited)
+				    $Tree.connect("item_edited", self, "on_Tree_item_edited")
 
 				func on_Tree_item_edited():
 				    print($Tree.get_edited()) # This item just got edited (e.g. checked).