Add REC Publication snapshot.

Author: gkellogg

index.html

@@ -7090,7 +7090,7 @@ <h2>Changes since Candidate Release of 05 March 2020</h2>
       the `preserve` keyword, which is only used for framing.</li>
   </ul>
 </section>
-<section class="appendix informative" id="changes-from-cr">
+<section class="appendix informative" id="changes-from-pr">
   <h2>Changes since Proposed Recommendation Release of 7 May 2020</h2>
   <ul>
     <li>Removed remaining "at-risk" notes.</li>