Add coreutils to macos to have proper gnuutils

lib/mksystem.nix

@@ -123,13 +123,16 @@ in
       ]
       ++ nixpkgs.lib.optionals darwin [
         inputs.nix-index-database.darwinModules.nix-index
-        {
+        ({pkgs, ...}: {
+          environment.systemPackages = with pkgs; [
+            coreutils
+          ];
           # auth sudo via fingerprint
           security.pam.services.sudo_local = {
             reattach = true;
             touchIdAuth = true;
           };
-        }
+        })
       ]
       ++ custom;
   }

nvim/lua/plugins/conform.lua

@@ -35,6 +35,9 @@ return {
 				},
 				csharpier = function()
 					return {
+						command = "csharpier",
+						args = { "format" },
+						stdin = true,
 						--- @diagnostic disable: param-type-mismatch
 						cwd = require("conform.util").root_file(function(name)
 							return name:match('.*%.sln$') or name:match('.*%.csproj$')