apply new nix fmt specification

templates/rust/flake.nix

@@ -1,7 +1,8 @@
 {
   description = "Basic Rust project";
   inputs.nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
-  outputs = { self, nixpkgs }:
+  outputs =
+    { self, nixpkgs }:
     let
       forAllSystems = nixpkgs.lib.genAttrs [
         "x86_64-linux"
@@ -9,10 +10,14 @@
         "aarch64-linux"
         "aarch64-darwin"
       ];
-    in {
-      devShells = forAllSystems (system:
-        let pkgs = import nixpkgs { inherit system; };
-        in {
+    in
+    {
+      devShells = forAllSystems (
+        system:
+        let
+          pkgs = import nixpkgs { inherit system; };
+        in
+        {
           default = pkgs.mkShell {
             buildInputs = with pkgs; [
               gcc
@@ -24,6 +29,7 @@
               openssl
             ];
           };
-        });
+        }
+      );
     };
 }