Tests: Add link to visual test for selectmenu to index

Author: jzaefferer

tests/visual/index.html

@@ -57,6 +57,11 @@ <h2>Position</h2>
 			<li><a href="position/position_feedback.html">Feedback</a></li>
 		</ul>
 
+		<h2>Selectmenu</h2>
+		<ul>
+			<li><a href="selectmenu/selectmenu.html">General</a></li>
+		</ul>
+
 		<h2>Tooltip</h2>
 		<ul>
 			<li><a href="tooltip/tooltip.html">General</a></li>