Fix intra doc link to diesel::sql_types
diff --git a/diesel_derives/src/lib.rs b/diesel_derives/src/lib.rs
index 6d2cdea..aae4f53 100644
--- a/diesel_derives/src/lib.rs
+++ b/diesel_derives/src/lib.rs
@@ -487,7 +487,7 @@
///
/// The syntax for this macro is very similar to that of a normal Rust function,
/// except the argument and return types will be the SQL types being used.
-/// Typically these types will come from [`diesel::sql_types`].
+/// Typically these types will come from [`diesel::sql_types`](../diesel/sql_types/index.html)
///
/// This macro will generate two items. A function with the name that you've
/// given, and a module with a helper type representing the return type of your
