Mark the auto margins section as non-normative.

--HG--
extra : rebase_source : 630a4f4ba7cdd163b804ebe1482f8fef8ee62641

Author: tabatkins

css3-flexbox/Overview.html

@@ -1405,6 +1405,8 @@ <h2 id=alignment><span class=secno>8. </span> Alignment</h2>
   <h3 id=auto-margins><span class=secno>8.1. </span> Aligning with
    &lsquo;<code class=css>auto</code>&rsquo; margins</h3>
 
+  <p> <em>This section is non-normative.</em>
+
   <p> Margins on flexbox items that are &lsquo;<code
    class=css>auto</code>&rsquo; have an effect very similar to auto margins
    in normal flow:

css3-flexbox/Overview.src.html

@@ -912,6 +912,9 @@ <h2 id='alignment'>
 <h3 id='auto-margins'>
 Aligning with ''auto'' margins</h3>
 
+	<p>
+		<em>This section is non-normative.</em>
+
 	<p>
 		Margins on flexbox items that are ''auto'' have an effect very similar to auto margins in normal flow: