e031c5ff6b
See https://discourse.nixos.org/t/i-cannot-for-the-life-of-me-find-the-package-that-has-pg-config/66244/4 I decided against doing this in its own nixpkgs manual: the line to draw is quite blurry already (e.g. we have documented our package removal policy in here as well) and having to check two manuals for a single subsystem feels pretty annoying to me. The relevant part - where to find pg_config - is written at the top. I decided to give a bit more context about the way our packaging works since I realized a few times now that I don't remember all the details about the problems we had in the past and having to look up individual commit messages for that isn't very productive.