docs: fix `ssizeobjargproc` parameters (GH-100736)

(cherry picked from commit 5fb1c08e15b864d8ea9353a0e013166e2e0e2160)

Co-authored-by: David Lechner <david@lechnology.com>
diff --git a/Doc/c-api/typeobj.rst b/Doc/c-api/typeobj.rst
index dc82620..aa2de33 100644
--- a/Doc/c-api/typeobj.rst
+++ b/Doc/c-api/typeobj.rst
@@ -450,6 +450,7 @@
 |                             |                             |                      |
 |                             |    :c:type:`PyObject` *     |                      |
 |                             |    :c:type:`Py_ssize_t`     |                      |
+|                             |    :c:type:`PyObject` *     |                      |
 +-----------------------------+-----------------------------+----------------------+
 | :c:type:`objobjproc`        | .. line-block::             | int                  |
 |                             |                             |                      |
@@ -2589,7 +2590,7 @@
 
 .. c:type:: PyObject *(*ssizeargfunc)(PyObject *, Py_ssize_t)
 
-.. c:type:: int (*ssizeobjargproc)(PyObject *, Py_ssize_t)
+.. c:type:: int (*ssizeobjargproc)(PyObject *, Py_ssize_t, PyObject *)
 
 .. c:type:: int (*objobjproc)(PyObject *, PyObject *)