clean up 'scope' decl

common/nix/nixpkgs.nix

@@ -1,7 +1,6 @@
 {
   inputs,
   lib,
-  scope,
   ...
 }:
 scope "nixpkgs" {

common/nix/substituters.nix

@@ -1,5 +1,4 @@
 {
-  scope,
   ...
 }:
 scope "nix.settings" {

common/nix/tools.nix

@@ -1,19 +1,15 @@
 {
   pkgs,
   inputs,
-  getPkgs,
   getFlakePkg,
   ...
 }:
 {
-  environment.systemPackages =
-    getPkgs {
-      inherit (pkgs)
-        nixfmt
-        nil
-        ;
-    }
-    ++ [ (getFlakePkg inputs.yoke) ];
+  environment.systemPackages = [
+    pkgs.nixfmt
+    (getFlakePkg inputs.yoke)
+    (getFlakePkg inputs.nil)
+  ];
   imports = [
     inputs.nix-index-database.nixosModules.nix-index
   ];