fix: Format example blocks

books/core/53.html

@@ -28,7 +28,7 @@
     fill two additional sections.
   </li>
 </ul>
-<p>
+<p class="example">
   <strong>Example:</strong> While sneaking her way through the monster-infested
   corridors of an ancient castle, Valea rolls a 6 on a Check with Difficulty
   Level 10. The Game Master fills two sections on the "Ambushed!" Clock — one