nix: Use 22.11 options

modules/nix.nix

@@ -21,9 +21,6 @@ let
 in
 {
   nix = {
-    # nix with flake support
-    package = pkgs.nixFlakes;
-
     registry = with inputs; {
       nixpkgs.flake = nixpkgs;
       nixpkgs-unstable.flake = nixpkgs-unstable;
@@ -33,18 +30,20 @@ in
       "nixpkgs=${inputs.nixpkgs}"
       "nixpkgs-overlays=${overlaysCompat}"
     ];
-    # Make sudoers trusted nix users
-    trustedUsers = [ "@wheel" ];
 
-    # On-the-fly optimisation of nix store
-    autoOptimiseStore = true;
-    extraOptions = ''
-      experimental-features = nix-command flakes
-    '' + lib.optionalString config.sbruder.full ''
+    settings = {
+      # Make sudoers trusted nix users
+      trusted-users = [ "@wheel" ];
+
+      # On-the-fly optimisation of nix store
+      auto-optimise-store = true;
+
+      experimental-features = "nix-command flakes";
+    } // (lib.optionalAttrs config.sbruder.full {
       # Keep output of derivations with gc root
-      keep-outputs = true
-      keep-derivations = true
-    '';
+      keep-outputs = true;
+      keep-derivations = true;
+    });
 
     # Make nix build in background less noticeable
     daemonCPUSchedPolicy = "batch";