remove declaration of nonexistent map_name_popup routine

include/map_name_popup.h

@@ -3,12 +3,6 @@
 
 #include "global.h"
 
-// Exported type declarations
-
-// Exported RAM declarations
-
-// Exported ROM declarations
-void HideMapNamePopUpWindow(void);
 void CreateMapNamePopupIfNotAlreadyRunning(bool32 palIntoFadedBuffer);
 
 #endif //GUARD_MAP_NAME_POPUP_H