Make StreamField migration a headline release note for 6.2

docs/releases/6.2.md

@@ -36,6 +36,10 @@ This feature was implemented by Albina Starykova, with support from the Wagtail
 
 All built-in and custom report views now use the Universal Listings visual design and filtering features introduced in all other listings in the admin interface over past releases. Thank you to Sage Abdullah for implementing this feature and continuing the rollout of the new designs.
 
+### Compact StreamField representation for migrations
+
+StreamField definitions within migrations are now represented in a more compact form, where blocks that appear in multiple places within a StreamField structure are only defined once. For complex and deeply-nested StreamFields, this considerably reduces the size of migration files, and the memory consumption when loading them. This feature was developed by Matt Westcott.
+
 ### Other features
 
  * Optimize and consolidate redirects report view into the index view (Jake Howard, Dan Braghis)
@@ -47,7 +51,6 @@ All built-in and custom report views now use the Universal Listings visual desig
  * Skip `ChooseParentView` if only one possible valid parent page availale (Matthias Brück)
  * Add `copy_for_translation_done` signal when a page is copied for translation (Arnar Tumi Þorsteinsson)
  * Remove reduced opacity for draft page title in listings (Inju Michorius)
- * Adopt more compact representation for StreamField definitions in migrations (Matt Westcott)
  * Implement a new design for locale labels in listings (Albina Starykova)
  * Add a `deactivate()` method to `ProgressController` (Alex Morega)
  * Allow manually specifying credentials for CloudFront frontend cache backend (Jake Howard)