fix: remove redundant access specifier

gtk/Application.cc

@@ -91,7 +91,6 @@ private:
         int stopped_count = 0;
     };
 
-private:
     void show_details_dialog_for_selected_torrents();
     void show_about_dialog();
 
@@ -153,7 +152,6 @@ private:
         tr_torrent* tor,
         gpointer gdata);
 
-private:
     Application& app_;
 
     std::string config_dir_;