I maintain that simply vanishing terms from the docs without any sort of explanation is a user-hostile action that we should fix and stop doing If we had something in the docs and we remove it, it's not unduly burdensome to have some index entries that point to the replacement/renamed terms, and a short appendix entry explaining what happened.
This sounds very reasonable to me. I would add that while I am by no means an expert in Postgres, although I do know a few things, I will state that it is my professional opinion as a Web person that pages should not simply disappear from formal documentation without some sort of indication of what happened. There are lots of ways to accomplish an indication but for https://www.postgresql.org/docs/current/recovery-config.html or other pages to just disappear is definitely wrong.