[css-cascade] Add 'author style sheet' and 'user style sheet' too.

Author: tabatkins

css-cascade/Overview.bs

@@ -752,11 +752,11 @@ Cascading Origins</h3>
 	CSS defines three core <a>origins</a>:
 
 	<dl>
-		<dt><dfn export id='cascade-origin-author'>Author Origin</dfn>
+		<dt><dfn export id='cascade-origin-author' lt="author origin|author style sheet">Author Origin</dfn>
 		<dd>
 			The author specifies style sheets for a source document according to the conventions of the document language. For instance, in HTML, style sheets may be included in the document or linked externally.
 
-		<dt><dfn export id='cascade-origin-user'>User Origin</dfn>
+		<dt><dfn export id='cascade-origin-user' lt="user origin|user style sheet">User Origin</dfn>
 		<dd>
 			The user may be able to specify style information for a particular document.
 			For example, the user may specify a file that contains a style sheet