4.0.6 release notes: a missing link

(cherry picked from commit 631a205)

Author: michaelklishin

release-notes/4.0.6.md

@@ -37,7 +37,7 @@ Release notes can be found on GitHub at [rabbitmq-server/release-notes](https://
 
    GitHub issue: [#13195](https://github.com/rabbitmq/rabbitmq-server/pull/13195)
 
- * When stream consumer was cancelled, an [internal event]() was not emitted.
+ * When stream consumer was cancelled, an [internal event](https://www.rabbitmq.com/docs/logging#internal-events) was not emitted.
 
    GitHub issues: [#13085](https://github.com/rabbitmq/rabbitmq-server/pull/13085), [#9356](https://github.com/rabbitmq/rabbitmq-server/pull/9356), [#13097](https://github.com/rabbitmq/rabbitmq-server/pull/13097)