Update _device_selection.py

Added a reference to where to find the list of all aspects

Author: oleksandr-pavlyk

dpctl/_device_selection.py

@@ -10,7 +10,9 @@ def select_device_with_aspects(required_aspects, excluded_aspects=[]):
     `required_aspects` list, and do not have any aspects in `excluded_aspects`
     list.
 
-    Supported
+    The list of SYCL device aspects can be found in SYCL 2020 specs:
+
+    https://www.khronos.org/registry/SYCL/specs/sycl-2020/html/sycl-2020.html#sec:device-aspects 
 
         :Example:
             .. code-block:: python