Release notes

docs/topics/3.0-announcement.md

@@ -8,6 +8,7 @@ Most notable outstanding issues still to resolved on the `version-3.0` branch.
 * Forms support for serializers and in the browsable API.
 * Enforcing uniqueness on `unique=True` and `unique_together` fields.
 * Optimisations for serialializing primary keys.
+* Refine style of validation errors in some cases, such as validation errors in `ListField`.
 
 # REST framework 3.0