conversions were done using https://github.com/pennae/nix-doc-munge
using (probably) rev f34e145 running
nix-doc-munge nixos/**/*.nix
nix-doc-munge --import nixos/**/*.nix
the tool ensures that only changes that could affect the generated
manual *but don't* are committed, other changes require manual review
and are discarded.
(It was requested by them.)
I left one case due to fetching from their personal repo:
pkgs/desktops/pantheon/desktop/extra-elementary-contracts/default.nix
