flake.nix: Improve nixosModules.notDetected error location reporting

[roberth]

Description of changes

This is mostly equivalent, but import was hiding the location from the module system, breaking error location reporting and breaking disabledModules support for this module (unlikely).

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandbox = true set in nix.conf? (See Nix manual)
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 22.11 Release Notes (or backporting 22.05 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
  • (Release notes changes) Ran nixos/doc/manual/md-to-db.sh to update generated release notes
• Fits CONTRIBUTING.md.

[Artturin]

getting this error in nix flake check

$ nix flake check --show-trace
evaluating flake...
warning: unknown flake output 'lib'
warning: unknown flake output 'htmlDocs'
error: module must be a function or an attribute set

       … while checking the NixOS module 'nixosModules.notDetected'

       at /home/artturin/nixgits/my-nixpkgs/flake.nix:59:9:

           58|       nixosModules = {
           59|         notDetected = ./nixos/modules/installer/scan/not-detected.nix;
             |         ^
           60|       };

       … while checking flake output 'nixosModules'

       at /home/artturin/nixgits/my-nixpkgs/flake.nix:58:7:

           57|
           58|       nixosModules = {
             |       ^
           59|         notDetected = ./nixos/modules/installer/scan/not-detected.nix;

https://github.com/NixOS/nix/blob/0efc314d4d1add3215810f9034b6041759d5175b/src/nix/flake.cc#L381-L405

[roberth]

That's a Nix bug. Paths are the best kind of module reference.

[roberth]

Noted by others as well NixOS/nix#6866