Add comment to ref a source

flake.nix

@@ -3,6 +3,7 @@
   # - https://github.com/BonusPlay/sysconf/blob/master/flake.nix (agenix)
   # - https://github.com/NixOS/infra/blob/master/build/flake.nix (agenix)
   # - https://johns.codes/blog/organizing-system-configs-with-nixos (caddy)
+  # - https://nixos-and-flakes.thiscute.world/nixos-with-flakes/start-using-home-manager
 
   description = "Pazpi's systems";
 
@@ -36,14 +37,15 @@
   };
 
   outputs =
-    { self
-    , nixpkgs
-    , nixos-hardware
-    , lix-module
-    , agenix
-    , colmena
-    , home-manager
-    , ...
+    {
+      self,
+      nixpkgs,
+      nixos-hardware,
+      lix-module,
+      agenix,
+      colmena,
+      home-manager,
+      ...
     }@inputs:
     let
       system = "x86_64-linux";