[w3c/webauthn] 9afddc: add comma to fix build

  Branch: refs/heads/jeffh-editorial-cleanups
  Home:   https://github.com/w3c/webauthn
  Commit: 9afddc391134f43bfaf9a8988ab93901c816a4df
      https://github.com/w3c/webauthn/commit/9afddc391134f43bfaf9a8988ab93901c816a4df
  Author: JeffH <Jeff.Hodges@PayPal.com>
  Date:   2016-09-15 (Thu, 15 Sep 2016)

  Changed paths:
    M index.bs

  Log Message:
  -----------
  add comma to fix build