docs: update several URLs to point to docs.named-data.net

Change-Id: If000753573c6a50130dc3101a411b6d482ccf3ed
diff --git a/docs/named_data_theme/named_data_header.html b/docs/named_data_theme/named_data_header.html
index 9179303..1bb6abc 100644
--- a/docs/named_data_theme/named_data_header.html
+++ b/docs/named_data_theme/named_data_header.html
@@ -32,7 +32,7 @@
 
          <!--top menu-->
          <div class="nine columns" id="menu_container" >
-           <h1><a href="https://named-data.net/doc/ndn-cxx/$projectnumber/">$projectname $projectnumber documentation</a></h1>
+           <h1><a href="https://docs.named-data.net/ndn-cxx/$projectnumber/">$projectname $projectnumber documentation</a></h1>
          </div>
     </div>
 </div><!--header container end-->