docs: improve Doxygen comments.

refs: #1435

Change-Id: I21624ef4eec393c82a50229a07e8277fb6ae4ddf
diff --git a/src/update/prefix-update-processor.hpp b/src/update/prefix-update-processor.hpp
index f316586..79e8070 100644
--- a/src/update/prefix-update-processor.hpp
+++ b/src/update/prefix-update-processor.hpp
@@ -43,7 +43,7 @@
 
 namespace security {
   class CertificateStore;
-}
+} // namespace security
 
 namespace update {
 
@@ -96,13 +96,13 @@
                uint32_t code,
                const std::string& text);
 
-  /** \brief adds desired name prefix to the advertised name prefix list
+  /*! \brief adds desired name prefix to the advertised name prefix list
    */
   void
   advertise(const std::shared_ptr<const ndn::Interest>& request,
             const ndn::nfd::ControlParameters& parameters);
 
-  /** \brief removes desired name prefix from the advertised name prefix list
+  /*! \brief removes desired name prefix from the advertised name prefix list
    */
   void
   withdraw(const std::shared_ptr<const ndn::Interest>& request,