simplify as per nix linter

lib.nix

@@ -1,5 +1,5 @@
 { pkgs, nix_templater }:
-rec {
+{
   # placeholder to be substituted with the content of a secret file
   fileContents = file: {
    outPath = "<${builtins.placeholder "nix_template"}${toString file}${builtins.placeholder "nix_template"}>";

tests/template.nix

@@ -8,7 +8,7 @@ in (nixpkgs.lib.nixos.runTest {
     hostPkgs = nixpkgs.legacyPackages.${system};
     name = "nix_templates";
 
-    nodes.machine = {config, pkgs, ...}: {
+    nodes.machine = {pkgs, ...}: {
       config = {
         systemd.services.testservice = {
           wantedBy = [ "multi-user.target" ];