Remove itemset and newbyteorder methods of dpnp.ndarray (#2141)

Author: antonwolfy

doc/reference/ndarray.rst

@@ -134,7 +134,6 @@ Array conversion
 
    dpnp.ndarray.item
    dpnp.ndarray.tolist
-   dpnp.ndarray.itemset
    dpnp.ndarray.tostring
    dpnp.ndarray.tobytes
    dpnp.ndarray.tofile

dpnp/dpnp_array.py

@@ -1087,8 +1087,6 @@ def item(self, id=None):
 
         return self.flat[id]
 
-    # 'itemset',
-
     @property
     def itemsize(self):
         """Size of one array element in bytes."""
@@ -1193,8 +1191,6 @@ def ndim(self):
 
         return self._array_obj.ndim
 
-    # 'newbyteorder',
-
     def nonzero(self):
         """
         Return the indices of the elements that are non-zero.