Whole-document visible deprecation

While discussing the question of updating or superseding/deprecating PEPs, it occurred to me that it would probably be a good idea to display PEPs that aren't active (have been superseded, rejected or otherwise no longer apply) in a way that their status is more apparent than just the one header line at the top, or (like PEP 302) a single note section at the top. If we could have a background text, background colour, floating notice on the side or any kind of visual indication that the text is not authoritative (anymore) even when following a direct link to a section in the PEP, that would be great.

该 issue 未指定文件、测试或入口点；首先确定 PEP 页面是如何渲染的，以及非活动状态是如何表示的。完成的标准是：即使直接链接打开某个章节，非活动 PEP 仍会被清晰标记为不具权威性。