Book: Added link to Part 2 of Yann's tutorial (#1103)

Author: Xophmeister

docs/book/src/guides/yann-tutorial.md

@@ -11,5 +11,13 @@ for a toy language, Yolo. Yann first guides you through the creation of
 a Tree-sitter grammar for Yolo, then plugs it into Topiary to write its
 formatting queries.
 
+## [Part 2]
+
+[Part 2] continues from where the previous part left off, by exploring
+some of the more advanced formatting features of Topiary, which are
+useful when handling real-life languages. In particular, it looks at
+single-line and multi-line layouts, using the Yolo toy language.
+
 <!-- Links -->
 [part 1]: https://www.tweag.io/blog/2025-01-30-topiary-tutorial-part-1
+[part 2]: https://www.tweag.io/blog/2025-10-02-topiary-tutorial-part-2