Switch to intra rustdoc links
diff --git a/codegen/src/fold.rs b/codegen/src/fold.rs
index b9f31bb..21e8f3b 100644
--- a/codegen/src/fold.rs
+++ b/codegen/src/fold.rs
@@ -248,7 +248,7 @@
             ///
             /// See the [module documentation] for details.
             ///
-            /// [module documentation]: index.html
+            /// [module documentation]: self
             ///
             /// *This trait is available if Syn is built with the `"fold"` feature.*
             pub trait Fold {