Move the definition of <ident> to V&U.

Author: tabatkins

css-values/Overview.bs

@@ -350,7 +350,8 @@ Property value examples</h3>
 <h2 id="textual-values">
 Textual Data Types</h2>
 
-	An <dfn>identifier</dfn> is a sequence of characters conforming to the <<ident-token>> grammar. [[!CSS3SYN]]
+	<dfn export lt="identifier|ident">Identifiers</dfn> are denoted by <dfn>&lt;ident></dfn>
+	and consist of a sequence of characters conforming to the <<ident-token>> grammar. [[!CSS3SYN]]
 	Identifiers cannot be quoted;
 	otherwise they would be interpreted as strings.
 

mediaqueries/Overview.bs

@@ -707,7 +707,6 @@ Syntax</h2>
 	</pre>
 
 	The <<media-type>> production does not include the keywords ''only'', ''not'', ''and'', and ''or''.
-	An <dfn>&lt;ident></dfn> is an <a>identifier</a>.
 
 	No whitespace is allowed between the “<” or “>” <<delim-token>>s and the following “=” <<delim-token>>,
 	if it's present.