docs: Documentation update

Change-Id: I6f916eb822a59e980e8fb1134886c3431755119c
diff --git a/utils/trie/trie.hpp b/utils/trie/trie.hpp
index 9ca8a28..28c075e 100644
--- a/utils/trie/trie.hpp
+++ b/utils/trie/trie.hpp
@@ -20,6 +20,8 @@
 #ifndef TRIE_H_
 #define TRIE_H_
 
+/// @cond include_hidden
+
 #include "ns3/ndnSIM/model/ndn-common.hpp"
 
 #include "ns3/ptr.h"
@@ -771,4 +773,6 @@
 } // ndn
 } // ns3
 
+/// @endcond
+
 #endif // TRIE_H_