DOC: Added MA support for (numpy#21262)

Author: ganesh-k13

doc/release/upcoming_changes/21262.improvement.rst

@@ -0,0 +1,34 @@
+``np.kron`` now maintains subclass information
+----------------------------------------------
+``np.kron`` maintains subclass information now such as masked arrays
+while computing the Kronecker product of the inputs
+
+.. code-block:: python
+
+    >>> x = ma.array([[1, 2], [3, 4]], mask=[[0, 1], [1, 0]])
+    >>> np.kron(x,x)
+    masked_array(
+      data=[[1, --, --, --],
+            [--, 4, --, --],
+            [--, --, 4, --],
+            [--, --, --, 16]],
+      mask=[[False,  True,  True,  True],
+            [ True, False,  True,  True],
+            [ True,  True, False,  True],
+            [ True,  True,  True, False]],
+      fill_value=999999)
+
+.. warning::
+    ``np.kron`` output now follows ``ufunc`` ordering (``multiply``)
+    to determine the output class type
+
+    .. code-block:: python
+
+        >>> class myarr(np.ndarray):
+        >>>    __array_priority__ = -1
+        >>> a = np.ones([2, 2])
+        >>> ma = myarray(a.shape, a.dtype, a.data)
+        >>> type(np.kron(a, ma)) == np.ndarray
+        False # Before it was True
+        >>> type(np.kron(a, ma)) == myarr
+        True