sys.hash_info.cutoff is missing in documentation

The [documentation of `sys.hash_info`](https://docs.python.org/3.10/library/sys.html#sys.hash_info) is missing the `cutoff` value in its table.

Both `print(sys.hash_info)` and `help(sys.hash_info)` show it.

[Source code](https://github.com/python/cpython/blob/544531de23d69f5b23883794fc7bb23a958a0fcb/Python/sysmodule.c#L1341) of its definition.