carapace: build-time nushell config generation

tests/modules/programs/carapace/nushell.nix

@@ -1,4 +1,4 @@
-{ pkgs, config, ... }:
+{ lib, pkgs, realPkgs, config, ... }:
 
 {
   programs = {
@@ -6,17 +6,16 @@
     nushell.enable = true;
   };
 
+  _module.args.pkgs = lib.mkForce realPkgs;
+
   nmt.script = let
     configDir = if pkgs.stdenv.isDarwin && !config.xdg.enable then
       "home-files/Library/Application Support/nushell"
     else
       "home-files/.config/nushell";
   in ''
-    assertFileExists "${configDir}/env.nu"
-    assertFileRegex "${configDir}/env.nu" \
-      '/nix/store/.*carapace.*/bin/carapace _carapace nushell \| save -f \$"(\$carapace_cache)/init\.nu"'
     assertFileExists "${configDir}/config.nu"
     assertFileRegex "${configDir}/config.nu" \
-      'source /.*/\.cache/carapace/init\.nu'
+      'source /nix/store/[^/]*-carapace-nushell-config'
   '';
 }