[fix] nvim: system module brok plugins

The architecture of nixvim doesn't let me use NixOS modules T-T, I need
to use manual imports instead.

nvim/default.nix

@@ -1,5 +1,14 @@
-args: {
+{
+  lib,
+  pkgs,
+  config,
+  helpers,
+  ...
+}: let
+  # Force inputs to be included
+  nixvim = import ./nixvim.nix {inherit lib pkgs config helpers;};
+in {
   imports = [./options.nix];
 
-  config.programs.nixvim = (import ./nixvim.nix args).config;
+  config.programs.nixvim = nixvim.config;
 }