refactor: pull out template filter into variable

flake.nix

@@ -16,6 +16,9 @@
         rust = "rust_cargo-nightly_crane+fenix";
       };
 
+      # Files to filter out of the template
+      template-ignore = [ "flake.lock" "Cargo.lock" ];
+
       # Get all subdirectories of the given path
       # Returns [str]
       subdirs = dir:
@@ -37,7 +40,7 @@
         ${concatStringsSep "_" subds} = {
           description = generateDesc subds;
           path = filterSource
-            (p: _: !(elem (baseNameOf p) [ "flake.lock" "Cargo.lock" ]))
+            (p: _: !(elem (baseNameOf p) template-ignore))
             (foldl' (dir: subd: /${dir}/${subd}) ./. subds);
         };
       }) (flakeSubdirs ./.) // mapAttrs (from: to: