I am learning rust and reading the book for the first time The [guessing-game](https://github.com/rust-lang/rust/blob/01d76099f261abe50342d9261fad618c5323274b/src/doc/book/guessing-game.md#complete) section mentions a "Next Project" at the very end > Our next project will show off even more. We can add a link to that project ?