Map the Android MENU button back to the SDL MENU key

Thanks to @AntTheAlchemist for the investigation!

Fixes https://github.com/libsdl-org/SDL/issues/7318

src/joystick/android/SDL_sysjoystick.c

@@ -180,6 +180,8 @@ static SDL_Scancode button_to_scancode(int button)
         return SDL_SCANCODE_ESCAPE;
     case SDL_GAMEPAD_BUTTON_BACK:
         return SDL_SCANCODE_ESCAPE;
+    case SDL_GAMEPAD_BUTTON_START:
+        return SDL_SCANCODE_MENU;
     case SDL_GAMEPAD_BUTTON_DPAD_UP:
         return SDL_SCANCODE_UP;
     case SDL_GAMEPAD_BUTTON_DPAD_DOWN: