Mod: modernize C++: use equals default

src/Mod/Start/App/AppStart.cpp

@@ -36,8 +36,6 @@ public:
         initialize("This module is the Start module."); // register with Python
     }
 
-    ~Module() override {}
-
 private:
 };
 

src/Mod/Start/Gui/AppStartGui.cpp

@@ -53,8 +53,6 @@ public:
         initialize("This module is the StartGui module."); // register with Python
     }
 
-    ~Module() override {}
-
 private:
 };
 

src/Mod/Start/Gui/DlgStartPreferencesImp.cpp

@@ -80,10 +80,7 @@ DlgStartPreferencesImp::DlgStartPreferencesImp( QWidget* parent )
 /**
  *  Destroys the object and frees any allocated resources
  */
-DlgStartPreferencesImp::~DlgStartPreferencesImp()
-{
-    // no need to delete child widgets, Qt does it all for us
-}
+DlgStartPreferencesImp::~DlgStartPreferencesImp() = default;
 
 void DlgStartPreferencesImp::saveSettings()
 {

src/Mod/Start/Gui/Workbench.cpp

@@ -42,13 +42,9 @@ using namespace StartGui;
 
 TYPESYSTEM_SOURCE(StartGui::Workbench, Gui::StdWorkbench)
 
-StartGui::Workbench::Workbench()
-{
-}
+StartGui::Workbench::Workbench() = default;
 
-StartGui::Workbench::~Workbench()
-{
-}
+StartGui::Workbench::~Workbench() = default;
 
 void StartGui::Workbench::activated()
 {