4.0.8 release notes fixes

(cherry picked from commit 45f0f1c)

Author: michaelklishin

release-notes/4.0.8.md

@@ -48,7 +48,7 @@ Release notes can be found on GitHub at [rabbitmq-server/release-notes](https://
 
    Contributed by @SimonUnge.
 
-   GitHub issue: #13669](https://github.com/rabbitmq/rabbitmq-server/pull/13669)
+   GitHub issue: [#13669](https://github.com/rabbitmq/rabbitmq-server/pull/13669)
 
 
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