AttributeError when calling addressof_ref in SyclContext

[diptorupd]

The attribute _ctx_ref was renamed to _ctxt_ref but the addressof_ref function was not updated. Calling SyclContext.addressof_ref causes and AttributeError for this reason:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "dpctl/_sycl_context.pyx", line 353, in dpctl._sycl_context.SyclContext.addressof_ref
AttributeError: 'dpctl._sycl_context.SyclContext' object has no attribute '_ctx_ref'