Proposed two new roles to support the description list elements in HTML5

I have proposed two new roles in the context of the list role to support the DT and DD elements in HTML5 for role parity:

listitemdescription role:
https://raw.githack.com/w3c/aria/issue504-description-list-roles/index.html#listitemdescription

listitemterm role:
https://raw.githack.com/w3c/aria/issue504-description-list-roles/index.html#listitemterm

Updated the list role definition to include the two new roles:
https://raw.githack.com/w3c/aria/issue504-description-list-roles/index.html#list

Question
Do we need to support the group role with listiemdescription and listitemterm?

NOTE: This proposal follows a similar pattern as extending menuitem with the  menuitemcheckbox and menuitemradio roles.

Jon Gunderson, Ph.D., CPWA
Coordinator of Accessible IT Group
University of Illinois at Urbana/Champaign
1207 S. Oak Street
Champaign, IL 61820

www: https://go.illinois.edu/jongund