Deprecate Parallax Background and Parallax Layer

doc/classes/ParallaxBackground.xml

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8" ?>
-<class name="ParallaxBackground" inherits="CanvasLayer" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../class.xsd">
+<class name="ParallaxBackground" inherits="CanvasLayer" deprecated="Use the [Parallax2D] node instead." xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../class.xsd">
 	<brief_description>
 		A node used to create a parallax scrolling background.
 	</brief_description>

doc/classes/ParallaxLayer.xml

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8" ?>
-<class name="ParallaxLayer" inherits="Node2D" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../class.xsd">
+<class name="ParallaxLayer" inherits="Node2D" deprecated="Use the [Parallax2D] node instead." xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../class.xsd">
 	<brief_description>
 		A parallax scrolling layer to be used with [ParallaxBackground].
 	</brief_description>