docs: Documentation update

Change-Id: I6f916eb822a59e980e8fb1134886c3431755119c
diff --git a/utils/trie/counting-policy.hpp b/utils/trie/counting-policy.hpp
index 4a74036..71331b7 100644
--- a/utils/trie/counting-policy.hpp
+++ b/utils/trie/counting-policy.hpp
@@ -20,6 +20,8 @@
 #ifndef COUNTING_POLICY_H_
 #define COUNTING_POLICY_H_
 
+/// @cond include_hidden
+
 #include <boost/intrusive/options.hpp>
 #include <boost/intrusive/list.hpp>
 
@@ -108,4 +110,6 @@
 } // ndn
 } // ns3
 
+/// @endcond
+
 #endif // COUNTING_POLICY_H_