Clarify changelog FF relationship

doc/development/feature_flags/development.md

@@ -24,8 +24,9 @@ end
 ```
 
 Features that are developed and are intended to be merged behind a feature flag
-should not include a changelog entry. The entry should be added in the merge
-request removing the feature flag. If the feature contains any DB migration it
+should not include a changelog entry. The entry should either be added in the merge
+request removing the feature flag or the merge request where the default value of
+the feature flag is set to true. If the feature contains any DB migration it
 should include a changelog entry for DB changes.
 
 In the rare case that you need the feature flag to be on automatically, use