ping: Code refactoring

Change-Id: I8b4e2c9dd3ba3adfae8d296a5635b048b35cf593
Refs: #3137
diff --git a/tools/ping/server/tracer.hpp b/tools/ping/server/tracer.hpp
index 1971f50..b8b6952 100644
--- a/tools/ping/server/tracer.hpp
+++ b/tools/ping/server/tracer.hpp
@@ -39,7 +39,7 @@
   Tracer(PingServer& pingServer, const Options& options);
 
   /**
-   * Prints ping information when interest received
+   * @brief Prints ping information when interest received
    * @param name interest name received
    */
   void
@@ -53,4 +53,4 @@
 } // namespace ping
 } // namespace ndn
 
-#endif //NDN_TOOLS_PING_SERVER_TRACER_HPP
\ No newline at end of file
+#endif // NDN_TOOLS_PING_SERVER_TRACER_HPP