Fix markup

Author: rhiaro

ns/index.html

@@ -454,7 +454,7 @@ <h2 id="w3c-document-13-april-2018"><abbr title="World Wide Web Consortium">W3C<
       <dd><code>http://www.w3.org/2006/vcard/ns#</code></dd>
     </dl>
 
-    <p><em>Note: The <b>as</b> namespace was changed from http to https in the JSON-LD context document with version 1.4 on 2017-02-21.  It was unfortunately not changed in this HTML namespace document until 2018-11-24.</p>
+    <p class="note">The <code>as</code> namespace was changed from http to https in the JSON-LD context document with version 1.4 on 2017-02-21.  It was unfortunately not changed in this HTML namespace document until 2018-11-24.</p>
 
   </section>