Map GameCube controller trigger clicks as misc3 and misc4

This is for consistency with the GC Ultimate controller and allows binding in Steam

src/joystick/SDL_gamepad.c

@@ -714,7 +714,7 @@ static GamepadMapping_t *SDL_CreateMappingForHIDAPIGamepad(SDL_GUID guid)
           product == USB_PRODUCT_EVORETRO_GAMECUBE_ADAPTER2 ||
           product == USB_PRODUCT_EVORETRO_GAMECUBE_ADAPTER3))) {
         // GameCube driver has 12 buttons and 6 axes
-        SDL_strlcat(mapping_string, "a:b0,b:b2,dpdown:b6,dpleft:b4,dpright:b5,dpup:b7,lefttrigger:a4,leftx:a0,lefty:a1~,rightshoulder:b9,righttrigger:a5,rightx:a2,righty:a3~,start:b8,x:b1,y:b3,hint:!SDL_GAMECONTROLLER_USE_GAMECUBE_LABELS:=1,", sizeof(mapping_string));
+        SDL_strlcat(mapping_string, "a:b0,b:b2,dpdown:b6,dpleft:b4,dpright:b5,dpup:b7,lefttrigger:a4,leftx:a0,lefty:a1~,rightshoulder:b9,righttrigger:a5,rightx:a2,righty:a3~,start:b8,x:b1,y:b3,misc3:b11,misc4:b10,hint:!SDL_GAMECONTROLLER_USE_GAMECUBE_LABELS:=1,", sizeof(mapping_string));
     } else if (vendor == USB_VENDOR_NINTENDO &&
                (guid.data[15] == k_eSwitchDeviceInfoControllerType_HVCLeft ||
                 guid.data[15] == k_eSwitchDeviceInfoControllerType_HVCRight ||