[SYCL][Doc] Simpler free function kernel enqueue (#19995)
Specify a simplified way to enqueue free function kernels without first
getting a kernel bundle. The style follows the enqueue functions in
"sycl_ext_oneapi_enqueue_functions".
Once the KHR extension "sycl_khr_free_function_commands" is finalized,
we may also add enqueue functions that follow that style. However, we
will first need to extend the `requirements` in that KHR to accept
kernel launch properties.
