Set aria attributes
Set aria attributes

- Set aria-controls on the controlling radio or checkbox
- Update aria-hidden and aria-expanded attributes as content is toggled
- Move to new functions for showing and hiding toggled content

gavboulton/govuk_elements,alphagov/govuk_elements,TFOH/govuk_elements,gavboulton/govuk_elements,joelanman/govuk_elements,TFOH/govuk_elements,gavboulton/govuk_elements,gavboulton/govuk_elements,alphagov/govuk_elements,alphagov/govuk_elements,joelanman/govuk_elements,alphagov/govuk_elements