Link to list of feature flags

such that users know what feature flags to enable before upgrading to
3.12.0

Author: ansd

release-notes/3.12.0.md

@@ -54,7 +54,7 @@ for release notes of other releases.
 
 ### Required Feature Flags
 
-RabbitMQ 3.12.0 will require all feature flags from the 3.11.x release series to be enabled before upgrading,
+RabbitMQ 3.12.0 will require [all feature flags from the 3.11.x release series to be enabled](https://www.rabbitmq.com/feature-flags.html#list-of-feature-flags) before upgrading,
 similarly to how [3.11.0 required all feature flags introduced before 3.9.0](https://blog.rabbitmq.com/posts/2022/07/required-feature-flags-in-rabbitmq-3.11/).
 
 If the feature flags are not enabled, RabbitMQ 3.12 and later nodes will refuse to start.