Some server class attributes are missing in socketserver docs

Documentation

While working with socketserver recently I noticed that the allow_reuse_port class attribute is not documented but the allow_reuse_address attribute is.

https://github.com/python/cpython/blob/f9a5a3a3ef34e63dc197156e9a5f57842859ca04/Lib/socketserver.py#L185-L198

In addition there's a couple of places we could clean up right now, for instance address_family is still grouped with the per-instance attributes rather than the class attributes, request_queue_size is only applicable to TCP, and there's another missing undocumented class attribute for specifying max packet size that is only applicable to UDP.

Linked PRs

• gh-128320

从 socketserver 文档开始，将其中的类属性描述与 Lib/socketserver.py 第 185-198 行附近的内容进行比较。完成标准是记录 allow_reuse_port，正确归类 address_family，明确 request_queue_size 适用于 TCP，并记录仅适用于 UDP 的最大数据包大小属性；issue 中已链接 gh-128320。