docs: Documentation update

Change-Id: I6f916eb822a59e980e8fb1134886c3431755119c
diff --git a/utils/trie/multi-policy.hpp b/utils/trie/multi-policy.hpp
index 534499f..01c8951 100644
--- a/utils/trie/multi-policy.hpp
+++ b/utils/trie/multi-policy.hpp
@@ -20,6 +20,8 @@
 #ifndef MULTI_POLICY_H_
 #define MULTI_POLICY_H_
 
+/// @cond include_hidden
+
 #include "detail/multi-type-container.hpp"
 #include "detail/multi-policy-container.hpp"
 #include "detail/functor-hook.hpp"
@@ -189,4 +191,6 @@
 } // ndn
 } // ns3
 
+/// @endcond
+
 #endif // MULTI_POLICY_H_