address reviewer comments

Author: vtavana

dpctl/tensor/_elementwise_funcs.py

@@ -151,7 +151,7 @@
 
 # U13: ==== EXP           (x)
 _exp_docstring = """
-exp(x, order='K')
+exp(x, out=None, order='K')
 
 Computes exponential for each element `x_i` for input array `x`.
 """
@@ -289,7 +289,7 @@
 
 # U30: ==== SIN         (x)
 _sin_docstring = """
-sin(x, order='K')
+sin(x, out=None, order='K')
 
 Computes sin for each element `x_i` for input array `x`.
 """