vars: use writeShellApplication to shellcheck generators

nixosModules/clanCore/vars/generator.nix

@@ -16,7 +16,7 @@ let
     ;
 
   promptToFile = name: ''
-    cat "$prompts/${name}" > "$out/${name}"
+    cat "$prompts"/${name} > "$out"/${name}
   '';
 
   promptsToFilesScript = concatMapStrings promptToFile;
@@ -25,8 +25,13 @@ let
 in
 {
   finalScript = mkOptionDefault (
-    pkgs.writeScript "generator-${config.name}" ''
-      set -eu -o pipefail
+    lib.getExe (
+      pkgs.writeShellApplication {
+        name = "generator-${config.name}";
+        text = ''
+          in="''${in:?}"
+          out="''${out:?}"
+          ${if config.prompts == { } then "" else ''prompts="''${prompts:?}"''}
 
           export PATH="${makeBinPath config.runtimeInputs}:${pkgs.coreutils}/bin"
 
@@ -53,7 +58,9 @@ in
           ''}
           ${promptsToFilesScript filePromptNames}
           ${config.script}
-    ''
+        '';
+      }
+    )
   );
 
   files = genAttrs filePromptNames (_name: { });