[w3c/webauthn] 215c75: Update index.bs

  Branch: refs/heads/balfanz-patch-4
  Home:   https://github.com/w3c/webauthn
  Commit: 215c7598199b568c5c426ceaad4372c229b09a88
      https://github.com/w3c/webauthn/commit/215c7598199b568c5c426ceaad4372c229b09a88
  Author: balfanz <dirk@balfanz.net>
  Date:   2017-10-11 (Wed, 11 Oct 2017)

  Changed paths:
    M index.bs

  Log Message:
  -----------
  Update index.bs