Release v2.9.0

Release v2.9.0

release-check: OK a98cbc8

Changelog

Added

• Toasts a host can extend (re-audit OVR-02 from Symfony Beacon): partials/_toasts.html.twig options
  toast_roles (false: no role per toast — the stack is the live region, no double announcement), timeouts (merged
  over {error: 8000, warning: 8000, default: 5000}; 0 keeps a toast until dismissed), toast_classes (toast,
  content, title, message, dismiss), toast_type_classes (per flash type, default) and
  toast_flash_slots (false: the flash_<type> slots stay on inline flashes only), and the blocks
  toast_attributes, toast_text and toast_dismiss_attributes. Defaults render as before.
  USAGE.