message: Applies feedback to CHANGELOG
diff: ### Enhancements
  * <New feature description> (PR [#????](https://github.com/realm/realm-core/pull/????))
  * Move the implementation of the Audit API to the open-source repo and update it to work with MongoDB Realm.
  +* Changed the signature of `Realm::async_cancel_transaction` to return a boolean indicating whether the removal of the scheduled callback was successful (true) or not (false). Previously, the method returned void. (PR [#5546](https://github.com/realm/realm-core/pull/5546))
  ### Fixed
  * <How do the end-user experience this issue? what was the impact?> ([#????](https://github.com/realm/realm-core/issues/????), since v?.?.?)
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  ### Internals
  -* Changed signature of `Realm::async_cancel_transaction` to return a boolean indicating whether the removal of the scheduled callback was successful (true) or not (false). The method returned void before.
  +* None.
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