Fix element anchor to "changes-since-cr2".

Author: gkellogg

index.html

@@ -6965,7 +6965,7 @@ <h2>Changes since Candidate Release of 12 December 2019</h2>
       as a direct input, which resolves a {{Promise}} boundary issue.</li>
   </ul>
 </section>
-<section class="appendix informative" id="changes-from-cr">
+<section class="appendix informative" id="changes-from-cr2">
   <h2>Changes since Candidate Release of 05 March 2020</h2>
   <p class="note">All changes are editorial and do not affect the observable
     behavior of the API nor the expected test results.</p>