nix: replace neovim option with package

modules/shell.nix

@@ -4,6 +4,7 @@
   programs.zsh.enable = true;
 
   environment.systemPackages = with pkgs; [
+    neovim
     git
     zoxide
     tlrc
@@ -37,13 +38,4 @@
     loadInNixShell = true;
     nix-direnv.enable = true;
   };
-
-  programs.neovim = {
-    enable = true;
-    vimAlias = true;
-    viAlias = true;
-    withRuby = true;
-    withPython3 = true;
-    withNodeJs = true;
-  };
 }