nixos/systemd-tmpfiles: use types.attrsWith for settings

[Ma27]

That way it's way easier to derive from the manual which key is used for what exactly.

This is possible now that #295872 is fixed.

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandboxing enabled in nix.conf? (See Nix manual)
  • sandbox = relaxed
  • sandbox = true
• 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/)
• 25.05 Release Notes (or backporting 24.11 and 25.05 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
• Fits CONTRIBUTING.md.

---

Add a 👍 reaction to pull requests you find important.

[WilliButz]

I'm very much in favor of giving those attributes proper names in the docs, but I'm not sure about the first one being called "rule-name". Since the corresponding manpage tmpfiles.d(5) does not mention "rule", I imagine this may cause some confusion for first time users of the module. I'd suggest naming it something like "config-name" or "package-name".

[Ma27]

but I'm not sure about the first one being called "rule-name".

Good idea :)
Wasn't sure how to name it either, so I just made something up, but I like your suggestion better ;-)