fix: update macros link in docs (#3767)

docs/content/docs/basics/program-structure.mdx

@@ -6,7 +6,7 @@ description:
 ---
 
 The Anchor framework uses
-[Rust macros](https://rust-book.cs.brown.edu/ch20-06-macros.html) to reduce
+[Rust macros](https://rust-book.cs.brown.edu/ch20-05-macros.html?highlight=macros#macros) to reduce
 boilerplate code and simplify the implementation of common security checks
 required for writing Solana programs.