[meta] Specialize the dfns to avoid ambi-for conflicts elsewhere.

Author: tabatkins

selectors/Overview.bs

@@ -564,7 +564,7 @@ Structure and Terminology</h3>
 	it defaults to meaning a <a>list of complex selectors</a>.
 	See [[#grouping]] for further details on <a>selector lists</a>.
 
-	The <dfn export local-lt="subject">subject of a selector</dfn> is
+	The <dfn export for=selector lt="subject|subject of a selector">subject of a selector</dfn> is
 	the element(s) that selector is defined to be about:
 
 	<ul>
@@ -574,7 +574,7 @@ Structure and Terminology</h3>
 		<li>For a <a>selector list</a>, it is any element that matches any of the <a>selectors</a> in the list.
 	</ul>
 
-	An element is said to <dfn export>match</dfn> a selector
+	An element is said to <dfn for=selector export>match</dfn> a selector
 	if it is a <a>subject</a> of that selector.
 	Thus a selector consisting of a single <a>compound selector</a>
 	matches any element satisfying its requirements.