Fix flake.nix indentation.

templates/nix-config/flake.nix

@@ -23,6 +23,8 @@
       inherit system;
       config.allowUnfree = true;
     };
+  in 
+  {
     nixosConfigurations = {
       numbus-server = nixpkgs.lib.nixosSystem {
         inherit system;
@@ -39,7 +41,7 @@
           # Core host configuration
           ./configuration.nix
           ./hardware-configuration.nix
-        ]
+        ];
       };
     };
   };