gh-121477: mention new PyLong_*Bytes() functions in PyLong_FromString() (#121478)

* gh-121477: mention new PyLong_*Bytes() functions in PyLong_FromString()

* Update Doc/c-api/long.rst

---------

Co-authored-by: Kumar Aditya <kumaraditya@python.org>

Author: skirpichev

Doc/c-api/long.rst

@@ -94,9 +94,9 @@ distinguished from a number.  Use :c:func:`PyErr_Occurred` to disambiguate.
    ignored.  If there are no digits or *str* is not NULL-terminated following the
    digits and trailing whitespace, :exc:`ValueError` will be raised.
 
-   .. seealso:: Python methods :meth:`int.to_bytes` and :meth:`int.from_bytes`
-      to convert a :c:type:`PyLongObject` to/from an array of bytes in base
-      ``256``. You can call those from C using :c:func:`PyObject_CallMethod`.
+   .. seealso:: :c:func:`PyLong_AsNativeBytes()` and
+      :c:func:`PyLong_FromNativeBytes()` functions can be used to convert
+      a :c:type:`PyLongObject` to/from an array of bytes in base ``256``.
 
 
 .. c:function:: PyObject* PyLong_FromUnicodeObject(PyObject *u, int base)