fix(nvim): conflict with using global packages

Now it is an error to override the pkgs if global packages are being
used.

flake-modules/nixos-modules.nix

@@ -2,17 +2,12 @@
 {
   flake.nixosModules =
     let
-      nvim-config =
-        { pkgs, ... }:
-        {
-          imports = [
-            inputs.nixvim.homeManagerModules.nixvim
-            (import ../nvim {
-              inherit (inputs) unstable;
-              inherit (pkgs) system;
-            })
-          ];
-        };
+      nvim-config = {
+        imports = [
+          inputs.nixvim.homeManagerModules.nixvim
+          ../nvim
+        ];
+      };
       homeManagerModuleSandalone = import ../home {
         inherit nvim-config;
         inherit (inputs) stylix;

flake-modules/nvim.nix

@@ -3,19 +3,15 @@
   flake.overlays.nixvim = inputs.nixvim.overlays.default;
 
   perSystem =
-    { pkgs, system, ... }:
+    { system, ... }:
     let
       nixvimLib = inputs.nixvim.lib.${system};
       nixvim = inputs.nixvim.legacyPackages.${system};
       testNvimModule = nixvimLib.check.mkTestDerivationFromNixvimModule;
       nvimModule = extraConfig: {
-        inherit pkgs;
-        extraSpecialArgs = {
-          inherit (inputs) unstable;
-          inherit system;
-        };
+        pkgs = inputs.unstable.legacyPackages.${system};
         module = {
-          imports = [ (import ../nvim/standalone.nix { standalone = true; }) ];
+          imports = [ ../nvim/standalone.nix ];
           config = extraConfig;
         };
       };

nvim/default.nix

@@ -1,4 +1,3 @@
-{ system, unstable }:
 { lib, config, ... }:
 let
   cfg = config.jhome.nvim;
@@ -7,9 +6,8 @@ in
   imports = [ ./options.nix ];
 
   config.programs.nixvim = lib.mkMerge [
-    (import ./standalone.nix { standalone = false; })
+    (import ./standalone.nix)
     (lib.mkIf cfg.enable {
-      nixpkgs = lib.mkForce { pkgs = import unstable { inherit system; }; };
       enable = true;
       defaultEditor = lib.mkDefault true;
       jhome.nvim = cfg;

nvim/standalone.nix

@@ -1,11 +1,4 @@
-{ standalone }:
-{
-  pkgs,
-  system,
-  unstable,
-  lib,
-  ...
-}:
+{ pkgs, ... }:
 {
   imports = [
     ./options.nix
@@ -17,7 +10,6 @@
 
   config = {
     withRuby = false;
-    nixpkgs = lib.optionalAttrs standalone { pkgs = unstable.legacyPackages.${system}; };
     globals.mapleader = " ";
     # Appearance
     colorschemes.gruvbox = {