nushell: support darwin config file locations

Previously the nushell module did not differentiate between Linux and
Darwin when deciding where to place config files, whereas nushell
does. This commit fixes that.

modules/programs/nushell.nix

@@ -6,6 +6,11 @@ let
 
   cfg = config.programs.nushell;
 
+  configDir = if pkgs.stdenv.isDarwin then
+    "Library/Application Support/nushell"
+  else
+    "${config.xdg.configHome}/nushell";
+
   linesOrSource = name:
     types.submodule ({ config, ... }: {
       options = {
@@ -110,16 +115,15 @@ in {
 
   config = mkIf cfg.enable {
     home.packages = [ cfg.package ];
-
-    xdg.configFile = mkMerge [
+    home.file = mkMerge [
       (mkIf (cfg.configFile != null || cfg.extraConfig != "") {
-        "nushell/config.nu".text = mkMerge [
+        "${configDir}/config.nu".text = mkMerge [
           (mkIf (cfg.configFile != null) cfg.configFile.text)
           cfg.extraConfig
         ];
       })
       (mkIf (cfg.envFile != null || cfg.extraEnv != "") {
-        "nushell/env.nu".text = mkMerge [
+        "${configDir}/env.nu".text = mkMerge [
           (mkIf (cfg.envFile != null) cfg.envFile.text)
           cfg.extraEnv
         ];

tests/modules/programs/nushell/example-settings.nix

@@ -1,4 +1,4 @@
-{ ... }:
+{ pkgs, ... }:
 
 {
   programs.nushell = {
@@ -19,12 +19,17 @@
 
   test.stubs.nushell = { };
 
-  nmt.script = ''
+  nmt.script = let
+    configDir = if pkgs.stdenv.isDarwin then
+      "home-files/Library/Application Support/nushell"
+    else
+      "home-files/.config/nushell";
+  in ''
     assertFileContent \
-      home-files/.config/nushell/config.nu \
+      "${configDir}/config.nu" \
       ${./config-expected.nu}
     assertFileContent \
-      home-files/.config/nushell/env.nu \
+      "${configDir}/env.nu" \
       ${./env-expected.nu}
   '';
 }