Update @GDScript.xml range docs to iterate backwards.

modules/gdscript/doc_classes/@GDScript.xml

@@ -227,8 +227,8 @@
 				To iterate over an [Array] backwards, use:
 				[codeblock]
 				var array = [3, 6, 9]
-				for i in range(array.size(), 0, -1):
-				    print(array[i - 1])
+				for i in range(array.size() - 1, -1, -1):
+				    print(array[i])
 				[/codeblock]
 				Output:
 				[codeblock]