fix broken link to Jon's WITS '22 talk

index.html

@@ -118,7 +118,7 @@ <h2 id="cooltt">The <span class="package-name"><span class="cool">cool</span>tt<
             <h3>Publications and talks</h3>
             <ul>
               <li>
-                S. <a href="https://www.jonmsterling.com/abstracts.html#sterling:2022:wits">Make Three To Throw Away: Frontiers in Homotopical Proof Assistants</a>. <em>Workshop on the Implementation of Type Systems</em> (keynote).
+                S. <a href="https://www.jonmsterling.com/sterling-2022-wits.xml">Make Three To Throw Away: Frontiers in Homotopical Proof Assistants</a>. <em>Workshop on the Implementation of Type Systems</em> (keynote).
               </li>
             </ul>