Fix heading in CHANGELOG (#3986)

Author: doughsay

CHANGELOG.md

@@ -292,7 +292,7 @@ To enable this, a new callback called `annotate_slot/4` was added. Custom implem
 * Ensure `push_patch` works during form recovery ([#3964](https://github.com/phoenixframework/phoenix_live_view/issues/3964))
 * Fix diff crash in LiveViewTest when rendering structs ([#3970](https://github.com/phoenixframework/phoenix_live_view/pull/3970))
 
-## Enhancements
+### Enhancements
 
 * Include form values from DOM in `Phoenix.LiveViewTest.submit_form/2` and `Phoenix.LiveViewTest.follow_trigger_action/2` to mimic browser behavior ([#3885](https://github.com/phoenixframework/phoenix_live_view/issues/3885))
 * Allow assigning generic hooks to type `Hook` ([#3955](https://github.com/phoenixframework/phoenix_live_view/issues/3955))