flake: add darwinModule

docs/manual/release-notes/rl-0.9.md

@@ -13,6 +13,18 @@
 
 ## Changelog {#sec-release-0-9-changelog}
 
+[taylrfnt](https://github.com/taylrfnt)
+
+- Introduce a `darwinModule` option for Darwin users. The ergonomics of
+  importing a `nixosModule` into a Darwin flake were less than ideal, and when
+  users fork and update npins, they are prone to encountering errors like the
+  following:
+
+  ```shell
+  (class: "nixos") cannot be imported into a module 
+  evaluation that expects class "darwin".
+  ```
+
 [suimong](https://github.com/suimong):
 
 - Fix `vim.tabline.nvimBufferline` where `setupOpts.options.hover` requires

flake.nix

@@ -53,6 +53,11 @@
             ''
             self.nixosModules.nvf;
         };
+
+        darwinModules = {
+          nvf = import ./flake/modules/nixos.nix {inherit lib inputs;};
+          default = self.darwinModules.nvf;
+        };
       };
 
       perSystem = {pkgs, ...}: {