Update CHANGELOG

CHANGELOG

@@ -55,6 +55,7 @@ v 8.9.0 (unreleased)
   - RepositoryCheck::SingleRepositoryWorker public and private methods are now instrumented
   - Improve issuables APIs performance when accessing notes !4471
   - External links now open in a new tab
+  - Markdown editor now correctly resets the input value on edit cancellation !4175
 v 8.8.4 (unreleased)
   - Ensure branch cleanup regardless of whether the GitHub import process succeeds
@@ -67,7 +68,6 @@ v 8.8.4 (unreleased)
   - Fix importer for GitHub comments on diff
   - Disable Webhooks before proceeding with the GitHub import
   - Added descriptions to notification settings dropdown
-  - Markdown editor now correctly resets the input value on edit cancellation !4175
 v 8.8.3
   - Fix 404 page when viewing TODOs that contain milestones or labels in different projects. !4312