Mark override for virtual destructors

PR #19348.

src/gui/interfaces/iguiapplication.h

@@ -39,7 +39,7 @@ class MainWindow;
 class IGUIApplication : public IApplication
 {
 public:
-    virtual ~IGUIApplication() = default;
+    ~IGUIApplication() override = default;
 
     virtual DesktopIntegration *desktopIntegration() = 0;
     virtual MainWindow *mainWindow() = 0;

src/gui/powermanagement/powermanagement_x11.h

@@ -41,7 +41,7 @@ class PowerManagementInhibitor final : public QObject
 
 public:
     PowerManagementInhibitor(QObject *parent = nullptr);
-    virtual ~PowerManagementInhibitor() = default;
+    ~PowerManagementInhibitor() override = default;
 
     void requestIdle();
     void requestBusy();