Update nix-develop and nix-direnv

Signed-off-by: Nikolaos Karaolidis <nick@karaolidis.com>

hosts/common/configs/user/console/nix-develop/template.nix

@@ -8,21 +8,35 @@
     };
 
     flake-utils = {
-      url = "github:numtide/flake-utils";
+      type = "github";
+      owner = "numtide";
+      repo = "flake-utils";
+      ref = "main";
+    };
+
+    treefmt-nix = {
+      type = "github";
+      owner = "numtide";
+      repo = "treefmt-nix";
+      ref = "main";
+
+      inputs.nixpkgs.follows = "nixpkgs";
     };
   };
 
   outputs =
-    { nixpkgs, ... }@inputs:
+    { self, nixpkgs, ... }@inputs:
     inputs.flake-utils.lib.eachDefaultSystem (
       system:
       let
         pkgs = nixpkgs.legacyPackages.${system};
+        treefmt = inputs.treefmt-nix.lib.evalModule pkgs ./treefmt.nix;
       in
       {
-        devShells.default = pkgs.mkShell { packages = [ ]; };
+        devShells.default = pkgs.mkShell { packages = with pkgs; [ ]; };
 
-        formatter = pkgs.nixfmt-rfc-style;
+        formatter = treefmt.config.build.wrapper;
+        checks.formatting = treefmt.config.build.check self;
       }
     );
 }