Update doc to mention that visual comment node is currently not visible

doc/classes/VisualShaderNodeComment.xml

@@ -2,6 +2,7 @@
 <class name="VisualShaderNodeComment" inherits="VisualShaderNodeResizableBase" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../class.xsd">
 	<brief_description>
 		A comment node to be placed on visual shader graph.
+		[b]Note:[/b] The comment node is going through a rework and thus not visible to the user now.
 	</brief_description>
 	<description>
 		A resizable rectangular area with changeable [member title] and [member description] used for better organizing of other visual shader nodes.