update navbar model zoo link (#9749)

* update navbar model zoo link

* update

Author: szha

docs/_static/mxnet-theme/navbar.html

@@ -34,7 +34,7 @@ <h1 id="logo-wrap">
             <li><a class="main-nav-link" href="{{url_root}}faq/index.html">FAQ</a></li>
             <li><a class="main-nav-link" href="{{url_root}}architecture/index.html">Architecture</a></li>
             <li><a class="main-nav-link" href="https://github.com/apache/incubator-mxnet/tree/master/example">Examples</a></li>
-            <li><a class="main-nav-link" href="{{url_root}}model_zoo/index.html">Model Zoo</a></li>
+            <li><a class="main-nav-link" href="{{url_root}}api/python/gluon/model_zoo.html">Gluon Model Zoo</a></li>
           </ul>
         </span>
 
@@ -83,7 +83,7 @@ <h1 id="logo-wrap">
                   <li><a tabindex="-1"  href="{{url_root}}faq/index.html">FAQ</a></li>
                   <li><a tabindex="-1"  href="{{url_root}}architecture/index.html">Architecture</a></li>
                   <li><a tabindex="-1"  href="https://github.com/apache/incubator-mxnet/tree/master/example">Examples</a></li>
-                  <li><a tabindex="-1"  href="{{url_root}}model_zoo/index.html">Model Zoo</a></li>
+                  <li><a tabindex="-1"  href="{{url_root}}api/python/gluon/model_zoo.html">Gluon Model Zoo</a></li>
                 </ul>
               </li>
               <li><a href="{{url_root}}architecture/index.html">Architecture</a></li>