[w3c/webauthn] f716b7: Copy changes from #736

  Branch: refs/heads/issue-184
  Home:   https://github.com/w3c/webauthn
  Commit: f716b7fcfa4be4566a88a6f7b18b51804e66c721
      https://github.com/w3c/webauthn/commit/f716b7fcfa4be4566a88a6f7b18b51804e66c721
  Author: Emil Lundberg <emil@yubico.com>
  Date:   2018-01-12 (Fri, 12 Jan 2018)

  Changed paths:
    M index.bs

  Log Message:
  -----------
  Copy changes from #736

As requested by @equalsJeffH at
https://github.com/w3c/webauthn/pull/736#issuecomment-357309766