Fix erratum reference.

Author: gkellogg

index.html

@@ -7107,7 +7107,7 @@ <h2>Changes since Recommendation of 16 July 2020</h2>
     <li>Added some clarifications to the algorithm of <a href="#iri-compaction"></a>.</li>
     <li>Added additional language to the
       <a href="#compaction-algorithm">Compaction Algorithm</a>
-      step <a href="#alg-compact-12_8_9_6_1 ">12.8.9.6.1</a> to first expand
+      step <a href="#alg-compact-12_8_9_6_1">12.8.9.6.1</a> to first expand
       <var>container key</var> before compacting it.</li>
   </ul>
 </section>