Using RGB color constants where appropiate

src/battle_anim_effects_3.c

@@ -3896,7 +3896,7 @@ static void AnimTask_FacadeColorBlend_Step(u8 taskId)
     }
     else
     {
-        BlendPalette(gTasks[taskId].data[2], 16, 0, RGB(0, 0, 0));
+        BlendPalette(gTasks[taskId].data[2], 16, 0, RGB_BLACK);
         DestroyAnimVisualTask(taskId);
     }
 }