[3.13] gh-130214: Document PyEllipsis_Type (GH-130215) (#130223)

gh-130214: Document `PyEllipsis_Type` (GH-130215)
(cherry picked from commit fc8c99a)

Co-authored-by: Yuki Kobayashi <[email protected]>

Author: miss-islington

Doc/c-api/slice.rst

@@ -118,6 +118,12 @@ Ellipsis Object
 ^^^^^^^^^^^^^^^
 
 
+.. c:var:: PyTypeObject PyEllipsis_Type
+
+   The type of Python :const:`Ellipsis` object.  Same as :class:`types.EllipsisType`
+   in the Python layer.
+
+
 .. c:var:: PyObject *Py_Ellipsis
 
    The Python ``Ellipsis`` object.  This object has no methods.  Like