wallust: fix config location on darwin

This fixes the path of the wallust config file to be under Library/Application Support/wallust when on Darwin, instead of assuming it always falls under the XDG_CONFIG_HOME (for whatever reason the owner of the Rust dirs package refuses to allow XDG on macOS, since it's non-standard)

modules/programs/wallust.nix

@@ -42,7 +42,15 @@ in
   config = mkIf cfg.enable {
     home.packages = lib.mkIf (cfg.package != null) [ cfg.package ];
 
-    xdg.configFile."wallust/wallust.toml" = mkIf (cfg.settings != { }) {
+    xdg.configFile."wallust/wallust.toml" =
+      mkIf (cfg.settings != { } && !pkgs.stdenv.hostPlatform.isDarwin)
+        {
+          source = tomlFormat.generate "wallust.toml" cfg.settings;
+        };
+
+    home.file."Library/Application Support/wallust/wallust.toml" =
+      mkIf (cfg.settings != { } && pkgs.stdenv.hostPlatform.isDarwin)
+        {
           source = tomlFormat.generate "wallust.toml" cfg.settings;
         };
   };

tests/modules/programs/wallust/wallust.nix

@@ -1,3 +1,7 @@
+{
+  pkgs,
+  ...
+}:
 {
   home.enableNixpkgsReleaseCheck = false;
   programs.wallust = {
@@ -9,8 +13,16 @@
     };
   };
 
-  nmt.script = ''
-    assertFileExists home-files/.config/wallust/wallust.toml
-    assertFileContent home-files/.config/wallust/wallust.toml ${./expected.toml}
+  nmt.script =
+    let
+      path =
+        if pkgs.stdenv.hostPlatform.isDarwin then
+          "home-files/Library/Application Support/wallust/wallust.toml"
+        else
+          "home-files/.config/wallust/wallust.toml";
+    in
+    ''
+      assertFileExists '${path}'
+      assertFileContent '${path}' ${./expected.toml}
     '';
 }