Use need_to_know instead of expectations

www.agileplannerapp.com/boards/173808/cards/8707

Expectations have been replaced in favor of a govspeak
field on editions. Related:

https://github.com/alphagov/govuk_content_models/pull/257
Merge pull request #696 from alphagov/need-to-know

Use need_to_know instead of expectations
Avoid nesting need_to_know within other lists

www.agileplannerapp.com/boards/173808/cards/8707
Merge pull request #697 from alphagov/need-to-know

Avoid nesting need_to_know within other lists