[css3-syntax] Have the 'consume a rule' function return a *syntax* error, not a parse error, to avoid confusion.

Author: tabatkins

css3-syntax/Overview.html

@@ -3815,7 +3815,7 @@ <h3 id=parse-a-rule><span class=secno>6.2. </span> <dfn
    <li> Invoke the <a href="#parser-state-machine">parser. </a>
 
    <li> If the returned <a href="#stylesheet"><i>stylesheet</i></a> contains
-    more than one rule in its value, return a parse error.
+    more than one rule in its value, return a syntax error.
     <p> Otherwise, return the first rule in the value of the <a
      href="#stylesheet"><i>stylesheet</i></a> it returns.
   </ol>

css3-syntax/Overview.src.html

@@ -3336,7 +3336,7 @@ <h3>
 
 		<li>
 			If the returned <i>stylesheet</i> contains more than one rule in its value,
-			return a parse error.
+			return a syntax error.
 
 			<p>
 				Otherwise,