Failing feature
Don't override options with defaults in builder
Basic workflow for creating/editing a stats announcement
Hook up display date & override for statistical release announcements
Make StatisticalReleaseAnnouncement search indexable
Remove duplication from Whitehall.searchable_classes

Both SupportingPage and DocumentCollection are now edition classes,
so do not need to be present in additional_classes
Use consistent naming for release announcements in controller code
Allow publications to be drafted from announcements
Add service listener to clear announcements on publishing

When an edition is published, we need to remove any announcements
associated with it so they no longer appear in the upcoming releases
tab. Also avoids a clash in the public site search results
Make sure announcements are removed from search on deletion
Add a display type to the search index for stats announcements
Handle statistical_release_announcement_id being a blank string
Searchable fields should not be private
Enhance selects on stats release announcement form
Extract and enhance document finder JS to make more generic

The primary change here is to also set the edition_id as well as the
document_id if the input field is present. This will allow the code to
be reused when linking statistical release announcements to editions.
Enhance Admin::EditionFilter to allow filtering by multiple sub-types
Allow document search to be filtered by type and subtype
Tweak form label based on styleguide
Include link back to edit announcement when present on publications

This is only displayed for pre-published editions as once they have
been published, the announcement is redundant and shouldn't be visible
on the site anymore.
Allow additional filter params to be passed into the document finder

This allows us to perform a narrower search, for example just
publications of type statistics.