Add link to C-S-S core tests in index.html (#408)

Author: jonathanKingston

index.html

@@ -141,6 +141,7 @@ <h2>Other</h2>
 	<li><a href='./windows-browser/script-injection/secureWorld_index.html'>Windows Browser: SecureWorld Script injection tests</a></li>
 	<li><a href='./content-scope-scripts/webcompat/'>Webcompat tests</a></li>
 	<li><a href='./content-scope-scripts/infra/'>C-S-S infra</a></li>
+	<li><a href='./content-scope-scripts/'>C-S-S core tests</a></li>
 	<li><a href='./content-scope-scripts/element-hiding/'>Element Hiding (C-S-S)</a></li>
 	<li><a href='./tools/reach-calculator.html'>Site Breakage Reach Calculator</a></li>
 </ul>