Inconsistency in "flake.nix explained"

In ["flake.nix explained", in the intro to `nixosSystem`](https://nixos-and-flakes.thiscute.world/nixos-with-flakes/nixos-flake-configuration-explained#simple-introduction-to-nixpkgs-lib-nixos-system) you mention the (now deprecated) `system` option in text but it's gone from the code example. I'd vote for also removing the `system` option from the text, but adding a note or similar explaining that it used to exist but is no longer needed and an alias to `nixpkgs.hostPlatform` and often set automatically. (Rationale for this note: a lot of guides still mention it) Thanks for your book, it's great to read.