Documentation for new -W regex support fails to mention length requirement

Documentation

-W will now support regex. The documentation says that “If it starts and ends with a forward slash (/)” the message field will be a regular expression. This is incorrect, there is an additional requirement that the field be at least two characters long. / is one character long and starts and ends with a forward slash, but it is not interpreted as a regex (it matches literal /).

Linked PRs

• gh-147969

首先找到关于 -W 新正则表达式支持的 CPython 文档，并阅读其中关于以斜杠开头和结尾的字段的措辞。将其与 issue 的长度要求进行比较；当文档准确描述这两个条件时，工作就完成了。