Add missing override keyword

src/input.cpp

@@ -2240,7 +2240,7 @@ public:
         }
         return true;
     }
-    bool keyEvent(QKeyEvent *event)
+    bool keyEvent(QKeyEvent *event) override
     {
         if (event->key() != Qt::Key_Escape) {
             return false;

src/platformsupport/scenes/qpainter/qpaintersurfacetexture.h

@@ -20,7 +20,7 @@ class KWIN_EXPORT QPainterSurfaceTexture : public SurfaceTexture
 public:
     explicit QPainterSurfaceTexture(QPainterBackend *backend);
 
-    bool isValid() const;
+    bool isValid() const override;
 
     QPainterBackend *backend() const;
     QImage image() const;