docs: Small update of the documentation

+ Adding reference to the used packet format to the TOC
diff --git a/examples/ndn-simple.cc b/examples/ndn-simple.cc
index 78993ee..dea70a0 100644
--- a/examples/ndn-simple.cc
+++ b/examples/ndn-simple.cc
@@ -66,10 +66,10 @@
   p2p.Install (nodes.Get (0), nodes.Get (1));
   p2p.Install (nodes.Get (1), nodes.Get (2));
 
-  // Install CCNx stack on all nodes
-  ndn::StackHelper ccnxHelper;
-  ccnxHelper.SetDefaultRoutes (true);
-  ccnxHelper.InstallAll ();
+  // Install NDN stack on all nodes
+  ndn::StackHelper ndnHelper;
+  ndnHelper.SetDefaultRoutes (true);
+  ndnHelper.InstallAll ();
 
   // Installing applications