New features:
- Add `block_types` index to zcatalog. By default it is only added for new Plone sites.
To add it to an existing site, run `plone.volto.upgrades.add_block_types_index` manually.
[margaridasp, davisagli] (4778)
Bug fixes:
- Change the implementation for finding nested blocks to use an IBlockVisitor adapter. davisagli (127)
- Fix missing translations for head_title field. davisagli (130)