Fix dartdoc generation
diff --git a/lib/package_config_types.dart b/lib/package_config_types.dart
index 482f82a..38b68ce 100644
--- a/lib/package_config_types.dart
+++ b/lib/package_config_types.dart
@@ -3,7 +3,13 @@
 // BSD-style license that can be found in the LICENSE file.
 
 /// A package configuration is a way to assign file paths to package URIs,
-/// and vice-versa,
+/// and vice-versa.
+
+/// {@canonicalFor package_config.InvalidLanguageVersion}
+/// {@canonicalFor package_config.LanguageVersion}
+/// {@canonicalFor package_config.Package}
+/// {@canonicalFor package_config.PackageConfig}
+/// {@canonicalFor errors.PackageConfigError}
 library package_config.package_config_types;
 
 export 'src/package_config.dart'