Update output dtypes for bitwise shift operations (#201)

Author: kgryte

spec/API_specification/elementwise_functions.md

@@ -352,7 +352,7 @@ Shifts the bits of each element `x1_i` of the input array `x1` to the left by ap
 
 -   **out**: _<array>_
 
-    -   an array containing the element-wise results. The returned array must have the same data type as `x1`.
+    -   an array containing the element-wise results. The returned array must have a data type determined by {ref}`type-promotion`.
 
 (function-bitwise_invert)=
 ### bitwise_invert(x, /)
@@ -416,7 +416,7 @@ This operation must be an arithmetic shift (i.e., sign-propagating) and thus equ
 
 -   **out**: _<array>_
 
-    -   an array containing the element-wise results. The returned array must have the same data type as `x1`.
+    -   an array containing the element-wise results. The returned array must have a data type determined by {ref}`type-promotion`.
 
 (function-bitwise_xor)=
 ### bitwise_xor(x1, x2, /)