Document pathlib with_segments duck typing for path object arguments

Some pathlib methods use the presence of a with_segments attribute to decide whether an argument is already a path object.

This behavior was changed in gh-128520 / GH-130199 for Python 3.14. The main pathlib reference documents PurePath.with_segments(), but it does not currently mention that methods such as PurePath.match() and Path.rename() use with_segments as this duck-typed marker.

This can surprise authors of path-like or path-adjacent classes that define with_segments without implementing os.PathLike. The docs should describe the current behavior so subclass and third-party path authors have a clear contract to work from.

Linked PRs

• gh-153394

从 pathlib 主参考文档中的 PurePath.with_segments() 文档开始，并检查对 PurePath.match() 和 Path.rename() 的引用。记录 with_segments 的存在被用作鸭子类型路径对象标记这一点，包括其对类路径对象和路径相邻类的含义；确认渲染后的文档解释了当前 Python 3.14 的行为。