Gui: MSVC requires a user-defined destructor of RecentFilesAction

otherwise the class declaration of Private is needed in the header file

src/Gui/Action.cpp

@@ -937,6 +937,11 @@ RecentFilesAction::RecentFilesAction ( Command* pcCmd, QObject * parent )
     restore();
 }
 
+RecentFilesAction::~RecentFilesAction()
+{
+    _pimpl.reset(nullptr);
+}
+
 /** Adds the new item to the recent files. */
 void RecentFilesAction::appendFile(const QString& filename)
 {

src/Gui/Action.h

@@ -240,6 +240,7 @@ class GuiExport RecentFilesAction : public ActionGroup
 
 public:
     explicit RecentFilesAction (Command* pcCmd, QObject * parent = nullptr);
+    ~RecentFilesAction() override;
 
     void appendFile(const QString&);
     void activateFile(int);