[css3-flexbox] Clarify clarification. :P

Author: fantasai

css3-flexbox/Overview.html

@@ -3968,8 +3968,10 @@ <h2 class=no-num id=changes>Changes</h2>
 
    <li> Clarify that ‘<a href="#align-content-stretch"><code
     class=property>stretch</code></a>’ checks for the <em>computed</em>
-    value of the cross-size property, which means that percentages that can't
-    be resolved at computed-value time aren't stretched.
+    value of the cross-size property being ‘<code class=css>auto</code>’,
+    which means that percentage cross-sizes that behave as ‘<code
+    class=css>auto</code>’ (because they don't resolve against definite
+    sizes) aren't stretched.
   </ul>
 
   <p>A <a

css3-flexbox/Overview.src.html

@@ -3267,7 +3267,9 @@ <h2 class="no-num" id="changes">Changes</h2>
 			Correct an omission in the flex-line size determination, so a single-line flexbox will size to its contents if it doesn't have a definite size.
 
 		<li>
-			Clarify that 'stretch' checks for the <em>computed</em> value of the cross-size property, which means that percentages that can't be resolved at computed-value time  aren't stretched.
+			Clarify that 'stretch' checks for the <em>computed</em> value of the cross-size property being ''auto'',
+			which means that percentage cross-sizes that behave as ''auto''
+			(because they don't resolve against definite sizes) aren't stretched.
 	</ul>
 
 	<p>A <a href="http://dev.w3.org/csswg/css3-flexbox/issues-lc-2012">Disposition of Last Call Comments</a> is available.