3nd -> 3rd in errata page

Author: marijnh

html/errata.html

@@ -11,7 +11,7 @@
 
 <article>
 
-<h1>Errata<div style="font-size: 70%"><a class="subtlelink" href="index.html">Eloquent JavaScript</a>, 3nd Edition</div></h2>
+<h1>Errata<div style="font-size: 70%"><a class="subtlelink" href="index.html">Eloquent JavaScript</a>, 3rd Edition</div></h2>
 
 <p>These are the known mistakes in the <strong>third edition</strong>
 of the book. For errata in the first edition,