Bug 23209 - fix status section

Added to SoTD that document was developed and approved by HTML A11y TF
(PFWG + HTML WG)

index.html

@@ -49,6 +49,7 @@
     </section>
     <section id="sotd">
     	<p class="warning"><strong>This document is subject to change without notice.</strong></p>
+      <p>This document was developed by and with the approval of the <a href="http://www.w3.org/WAI/PF/html-accessibility-tf.html">HTML Accessibility Taskforce</a>, a joint task force of the <a href="http://www.w3.org/WAI/PF/">Protocols and Formats Working Group</a> and the <a href="http://www.w3.org/html/wg/">HTML Working Group</a>.</p>
     </section>
     <section class='informative'>
         <h2>Introduction: Accessibility <abbr title="Application Programming Interfaces">APIs</abbr></h2>