Add vector_fe_ex8 to examples TOC

Author: jwpeterson

examples.html

@@ -200,6 +200,8 @@ <h1>A Series of Example Programs</h1>
 
 <li><L1><a href="examples/vector_fe_ex7.html">Hybridized Raviart-Thomas Elements</a></L1></li>
 
+<li><L1><a href="examples/vector_fe_ex8.html">Single Face Hybridizable Discontinuous Galerkin</a></L1></li>
+
 </ol> </li>