mb.h: Fixed method overriding issue in CMenuSelector class

- Fixed the getHeight() method in CMenuSelector using the override keyword
  to ensure it correctly overrides the virtual method from CMenuItem.
- Resolved -Woverloaded-virtual warnings related to hidden overloaded
  virtual methods.

src/gui/moviebrowser/mb.h

@@ -377,7 +377,7 @@ class CMenuSelector : public CMenuItem
 		CMenuSelector(const char * OptionName, const bool Active , std::string & OptionValue, int* ReturnInt = NULL,int ReturnIntValue = 0);
 		int exec(CMenuTarget* parent);
 		int paint(bool selected);
-		int getHeight(void) const{return height;};
+		int getHeight(void) override {return height;};
 		bool isSelectable(void) const {	return active;}
 };