Suggested improvement to API docs

[diptorupd]

I need to use the max_work_item_sizes property of SyclDevice in Numba-dpex. The API doc does not specify the return type of the property, nor does it specify the deprecation warning. Both these things should be specified in the docstring so that one does not need to refer the source code.

[oleksandr-pavlyk]

Following changes in DPC++, dpctl.SyclDevice.max_work_item_sizes is deprecated, superseded by

• dpctl.SyclDevice.max_work_item_sizes1d
• dpctl.SyclDevice.max_work_item_sizes2d
• dpctl.SyclDevice.max_work_item_sizes3d