This fixes an issue where previously homeManagerModules would be an
unknown flake output. Note that this change is a part of Nix 2.22.3
but not Nix 2.23.3.
This fixes an issue where previously the derivation had to be evaluated
before importing the base16 scheme, thus causing `nix flake check` to
fail when multi-platform support was added.
See: https://github.com/NixOS/nix/issues/4265