Add link to docs generated by clang-doc

Change-Id: I77cc018edb6db86e49a603e4fbb163cc5724f0f0
diff --git a/public/index.html b/public/index.html
index b5e7b8d..a2559ee 100644
--- a/public/index.html
+++ b/public/index.html
@@ -25,6 +25,7 @@
   <ul>
         <li><a href="dart/index.html">Dart APIs</a></li>
         <li><a href="rust/fuchsia_component/index.html">Rust APIs</a></li>
+        <li><a href="cpp/index.html">C++ APIs</a></li>
   </ul>
 </div>