Added window_center() at Border_SetEnabled | 在Border_SetEnabled中添加window_center()

[SheepYhangCN]

GameMaker更新后 设置窗口大小的操作不会自动居中窗口 需要手动执行window_center()函数

After GameMaker updated, setting the window size wont automatically center the window Need to manual execute function window_center()