Add note that changes are editorial.

Author: gkellogg

index.html

@@ -6841,6 +6841,8 @@ <h4>JsonLdErrorCode</h4>
 </section>
 <section class="appendix informative" id="changes-from-cr">
   <h2>Changes since Candidate Release of 12 December 2019</h2>
+  <p class="note">All changes are editorial and do not affect the observable
+    behavior of the API nor the expected test results.</p>
   <ul>
     <li>Add `application/xhtml+xml` as an allowed media type in <a href="#process-html" class="sectionRef"></a>,
       in the note in <a href="#loaddocumentcallback" class="sectionRef"></a>,