Add latex residue in the exercise solutions to errata

Author: marijnh

html/errata.html

@@ -122,4 +122,11 @@ <h2>Chapter 21</h2>
 paragraph the <code>changesSince</code> parameter is incorrectly
 referred to as <code>changeSince</code> (singular).</p>
 
+<h2>Exercise Hints</h2>
+
+<p><strong>Page 409</strong> (Reversing an Array): The
+example <code>for</code> loop near the bottom of the page
+says <code>\textgreater{}</code> where it should
+say <code>&gt;</code>.
+
 </article>