Re-add previously removed NumPy C-API functions, following the same change in NumPy.

https://github.com/numpy/numpy/pull/16170/commits/e00d94b70880b1321eff727ac7eb897be7422340

Cython/Includes/numpy/__init__.pxd

@@ -565,8 +565,8 @@ cdef extern from "numpy/arrayobject.h":
     # more than is probably needed until it can be checked further.
     int PyArray_SetNumericOps        (object)
     object PyArray_GetNumericOps ()
-    # int PyArray_INCREF (ndarray)
-    # int PyArray_XDECREF (ndarray)
+    int PyArray_INCREF (ndarray)
+    int PyArray_XDECREF (ndarray)
     void PyArray_SetStringFunction (object, int)
     dtype PyArray_DescrFromType (int)
     object PyArray_TypeObjectFromType (int)
@@ -644,8 +644,8 @@ cdef extern from "numpy/arrayobject.h":
     #int PyArray_CompareUCS4 (npy_ucs4 *, npy_ucs4 *, register size_t)
     int PyArray_RemoveSmallest (broadcast)
     int PyArray_ElementStrides (object)
-    # void PyArray_Item_INCREF (char *, dtype)
-    # void PyArray_Item_XDECREF (char *, dtype)
+    void PyArray_Item_INCREF (char *, dtype)
+    void PyArray_Item_XDECREF (char *, dtype)
     object PyArray_FieldNames (object)
     object PyArray_Transpose (ndarray, PyArray_Dims *)
     object PyArray_TakeFrom (ndarray, object, int, ndarray, NPY_CLIPMODE)