Change List to Sequence in result_type annotation

Author: rgommers

spec/API_specification/utility_functions.md

@@ -79,7 +79,7 @@ If mixed dtypes (e.g. integer and floating-point) are used, the output of
 
 #### Parameters
 
--   **arrays_and_dtypes**: _List\[Union\[<array>, <dtype>\]\];_
+-   **arrays_and_dtypes**: _Sequence\[Union\[<array>, <dtype>\]\];_
 
     -   input arrays and dtypes.