Previously, the location logic was hardcoded, supporting only
Nixpkgs and NixOps properly, leaving other uses of the module
system without good location support.
to do this we must replace derivations with attrsets in make-options-doc, since
xml can represent derivations differently from attrset but json cannot. this
also given asciidoc and mddoc the ability to handle derivation differently,
which they previously didn't have.
Motivation is to support other repositories containing nixos
modules that would like to generate options documentation:
- nix-darwin
- private repos
- arion
- ??
