Updated draft for Issue 504 description list roles

Based on JN feedback, I have updated the proposal for the description list roles<https://raw.githack.com/w3c/aria/issue504-description-list-roles/index.html#descriptionitem>:
https://raw.githack.com/w3c/aria/issue504-description-list-roles/index.html#descriptionitem

Please provide feedback and comments in pull request 951<https://github.com/w3c/aria/pull/951>:
https://github.com/w3c/aria/pull/951

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