gh-95778: Fix `sys.set_int_max_str_digits()` parameter name (GH-96798)

Discovered in https://github.com/python/typeshed/pull/8733


(cherry picked from commit bf5fd492)

Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>

Doc/library/sys.rst

@@ -1331,7 +1331,7 @@ always available.
 
    .. availability:: Unix.
 
-.. function:: set_int_max_str_digits(n)
+.. function:: set_int_max_str_digits(maxdigits)
 
    Set the :ref:`integer string conversion length limitation
    <int_max_str_digits>` used by this interpreter. See also