Fixed ambiguity in linear gradient serialization.

Author: tabatkins

css3-images/Overview.html

@@ -1944,8 +1944,12 @@ <h3 id=serializing-gradients><span class=secno>7.6. </span>Serializing
         keyword, serialize the keyword and append it to s.
 
        <li>Otherwise, if the first argument to the gradient function was two
-        keywords, serialize both keywords. Append them, separated by a space
-        " ", to s.
+        keywords, serialize the vertical keyword (&lsquo;<code
+        class=css>top</code>&rsquo; or &lsquo;<code
+        class=css>bottom</code>&rsquo;) and append it to s, then append a
+        space " " to s, then serialize the horizontal keyword (&lsquo;<code
+        class=css>left</code>&rsquo; or &lsquo;<code
+        class=css>right</code>&rsquo;) and append it to s.
 
        <li>Otherwise, if the first argument to the gradient function was an
         &lt;angle>, serialize the &lt;angle> and append it to s.

css3-images/Overview.src.html

@@ -1365,8 +1365,9 @@ <h3 id="serializing-gradients">Serializing Gradients</h3>
 					keyword, serialize the keyword and append it to s.</li>
 
 					<li>Otherwise, if the first argument to the gradient function was 
-					two keywords, serialize both keywords.  Append them, separated by 
-					a space " ", to s.</li>
+					two keywords, serialize the vertical keyword (''top'' or ''bottom'')
+					and append it to s, then append a space " " to s, then serialize
+					the horizontal keyword (''left'' or ''right'') and append it to s.</li>
 
 					<li>Otherwise, if the first argument to the gradient function was 
 					an &lt;angle>, serialize the &lt;angle> and append it to s.</li>