Change types.attrs to recursively merge

[sorpaas]

Motivation for this change

This is a simple change to make types.attrs use recurisve update merge strategy. I currently cannot think of anything that this change may break, but not sure if I missed anything. So just putting this out for discussion.

Fixes #32217

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS linux)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.

[infinisil]

I'm not a fan of this attrs type because it's very much like attrsOf unspecified in that the values aren't given a type. In my opinion attrs should be deprecated and at the relevant locations replaced with whatever the fully specified type is. See also NixOS/rfcs#42 and #75584 which is relevant for this.

[stale]

Thank you for your contributions.

This has been automatically marked as stale because it has had no activity for 180 days.

If this is still important to you, we ask that you leave a comment below. Your comment can be as simple as "still important to me". This lets people see that at least one person still cares about this. Someone will have to do this at most twice a year if there is no other activity.

Here are suggestions that might help resolve this more quickly:

1. Search for maintainers and people that previously touched the related code and @ mention them in a comment.
2. Ask on the NixOS Discourse.
3. Ask on the #nixos channel on irc.freenode.net.

[stale]

I marked this as stale due to inactivity. → More info

[Mic92]

We have the settings options that can do this. And many services are migrated to this already.