Update cpp custom ops docs with sycl extension and xpu support #4519

Job	Run time
pytorch_tutorial_build_worker (5, 15, linux.g5.4xlarge.nvidia.gpu)	22m 32s
pytorch_tutorial_build_worker (1, 15, linux.g5.12xlarge.nvidia.gpu)	15m 25s
pytorch_tutorial_build_worker (4, 15, linux.g5.4xlarge.nvidia.gpu)	34m 45s
pytorch_tutorial_build_worker (2, 15, linux.g5.4xlarge.nvidia.gpu)	41m 41s
pytorch_tutorial_build_worker (12, 15, linux.g5.4xlarge.nvidia.gpu)	20m 25s
pytorch_tutorial_build_worker (3, 15, linux.g5.4xlarge.nvidia.gpu)	22m 4s
pytorch_tutorial_build_worker (8, 15, linux.g5.4xlarge.nvidia.gpu)	27m 15s
pytorch_tutorial_build_worker (14, 15, linux.g5.4xlarge.nvidia.gpu)	26m 11s
pytorch_tutorial_build_worker (10, 15, linux.g5.4xlarge.nvidia.gpu)	16m 40s
pytorch_tutorial_build_worker (9, 15, linux.g5.4xlarge.nvidia.gpu)	17m 41s
pytorch_tutorial_build_worker (15, 15, linux.g5.4xlarge.nvidia.gpu)	32m 32s
pytorch_tutorial_build_worker (11, 15, linux.g5.4xlarge.nvidia.gpu)	15m 18s
pytorch_tutorial_build_worker (6, 15, linux.g5.4xlarge.nvidia.gpu)	22m 9s
pytorch_tutorial_build_worker (7, 15, linux.g5.4xlarge.nvidia.gpu)	20m 47s
pytorch_tutorial_build_worker (13, 15, linux.g5.4xlarge.nvidia.gpu)	28m 15s
pytorch_tutorial_build_manager	23m 12s
	6h 26m 52s

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