Mentions are not accessible to users with a screen reader

Issue Summary

For visually impaired users who make use of a Screen Reader (such as NVDA or Jaws)

Environment

• JAWS version 2018.1804.26:
  • Chrome 65.0.3325.181
  • Firefox 64.0.2
• NVDA version 2018.4.1:
  • Chrome 65.0.3325.181

Steps to Reproduce

1. Install a screen reader of your choice
2. Mention a user

Expected Results

The screen reader should read aloud the names of the users in the mention picker.

Actual Results

The screen reader does not read the names of users in the mention picker.

Notes

JAWS can see the change in focus from the textbox to the suggestion panel, but cannot read issues from it.

Workaround

Currently there is no known workaround for this behavior.