[GUI] Add context manager support for ui.Gui (#3055)
[GUI] Add context manager support for ui.Gui (#3055)

* [python] Add context manager support for ui.Gui

Signed-off-by: Xuanwo <64b2b6d12bfe4baae7dad3d018f8cbf6b0e7a044@xuanwo.io>

* Add args for __exit__

Signed-off-by: Xuanwo <64b2b6d12bfe4baae7dad3d018f8cbf6b0e7a044@xuanwo.io>

* Fix the wrong usage of __enter__

Signed-off-by: Xuanwo <64b2b6d12bfe4baae7dad3d018f8cbf6b0e7a044@xuanwo.io>

* Rename to sub_window

Signed-off-by: Xuanwo <64b2b6d12bfe4baae7dad3d018f8cbf6b0e7a044@xuanwo.io>

* Update comments

Signed-off-by: Xuanwo <64b2b6d12bfe4baae7dad3d018f8cbf6b0e7a044@xuanwo.io>

* Update comments for sub_window

Signed-off-by: Xuanwo <64b2b6d12bfe4baae7dad3d018f8cbf6b0e7a044@xuanwo.io>

* Fix comment style

Signed-off-by: Xuanwo <64b2b6d12bfe4baae7dad3d018f8cbf6b0e7a044@xuanwo.io>
yuanming-hu/taichi,yuanming-hu/taichi,yuanming-hu/taichi,yuanming-hu/taichi