[Charter] Qualify accessibility in scope section

Feedback received during internal review. The update is editorial in essence,
and not intended to change the scope in any way. The "accessibility" bullet
just seemed to be hanging out without connection to the rest.

charters/charter-2019.html

@@ -166,7 +166,7 @@ <h2>Scope</h2>
           <li>media providers (streaming web sites, terrestrial, cable, IPTV, satellite systems)</li>
           <li>media production (capture, identification, metadata, content enrichment)</li>
           <li>media transport and control (formats, packaging, storage, synchronization)</li>
-          <li>accessibility</li>
+          <li>accessibility of media experiences and standards</li>
         </ul>
 
         <p>The tasks that the Interest Group will undertake include: </p>