Accessibility issue on the expand/collapse (should be listed as headings)

[lmichaud]

Current WET library has expand/collapse as regular containers (not headers) breaking accessibility. Need to raise as an issue on main WET repo.

[thomasgohard]

Assistive technologies don't support headings in the details/summary elements (which are used for the expand collapse). That's why WET (and the MWS) don't support putting headings in that component. That issue was documented as part of IRCC's migration to the MWS; although I don't know if it was formally documented in WET.