Whole-document visible deprecation #2719
Description
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PEPs, it occurred to me that it would probably be a good idea to display PEPs that aren't active (have been superseded, rejected or otherwise no longer apply) in a way that their status is more apparent than just the one header line at the top, or (like PEP 302) a single note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.