[selectors-4] export term

Author: fantasai

selectors-4/Overview.bs

@@ -2968,7 +2968,7 @@ The User-interaction Pseudo-classes: '':user-valid'' and '':user-invalid''</h4>
 <h2 id="structural-pseudos">
 Tree-Structural pseudo-classes</h2>
 
-	Selectors introduces the concept of <dfn id="structural-pseudo-classes">structural pseudo-classes</dfn>
+	Selectors introduces the concept of <dfn export id="structural-pseudo-classes">structural pseudo-classes</dfn>
 	to permit selection based on extra information that lies in
 	the document tree but cannot be represented by other simple selectors or
 	combinators.