Packages marked as broken should come with an explanation

[fricklerhandwerk]

@tysonzero

It’d be really nice if broken was more of a Maybe Text than a Bool so that it always came with an explanation, so that I can know what to watch out for if I choose to override it.

There is PR to do something like that: Stdenv overhaul `broken` flag by teto · Pull Request #140325 · NixOS/nixpkgs · GitHub