docs: fix several doxygen errors

Change-Id: If86c628b2b794cba0e3697bfe1d88ce752104ce1
Refs: #3210
diff --git a/src/lp/nack.hpp b/src/lp/nack.hpp
index 9512749..5fb57da 100644
--- a/src/lp/nack.hpp
+++ b/src/lp/nack.hpp
@@ -35,7 +35,7 @@
 
 /**
  * \brief represents a Network NACK
- * \detail This type binds a NackHeader and an Interest, and is intended for use in network layer.
+ * \details This type binds a NackHeader and an Interest, and is intended for use in network layer.
  */
 class Nack : public TagHost
 {
@@ -109,4 +109,4 @@
 } // namespace lp
 } // namespace ndn
 
-#endif // NDN_CXX_LP_NACK_HPP
\ No newline at end of file
+#endif // NDN_CXX_LP_NACK_HPP
diff --git a/src/lp/packet.hpp b/src/lp/packet.hpp
index 0febb75..53b998d 100644
--- a/src/lp/packet.hpp
+++ b/src/lp/packet.hpp
@@ -67,7 +67,7 @@
 public: // field access
   /**
    * \return true if FIELD occurs one or more times
-   * \detail This is equivalent to count()>0
+   * \details This is equivalent to count() > 0
    */
   template<typename FIELD>
   bool
@@ -136,7 +136,7 @@
 
   /**
    * \brief remove all occurrences of FIELD, and add a FIELD with value
-   * \detail This equivalent to clear() followed by add(value)
+   * \details This equivalent to clear() followed by add(value)
    */
   template<typename FIELD>
   Packet&