[w3c/webauthn] e21421: dfn tag closed by a tag - corrected. See #306

  Branch: refs/heads/jeffh-editorial-cleanups4
  Home:   https://github.com/w3c/webauthn
  Commit: e2142173c76914f0824ff517ddb492d703a4fa20
      https://github.com/w3c/webauthn/commit/e2142173c76914f0824ff517ddb492d703a4fa20
  Author: rlin1 <rolf@noknok.com>
  Date:   2016-12-07 (Wed, 07 Dec 2016)

  Changed paths:
    M index.bs

  Log Message:
  -----------
  dfn tag closed by a tag - corrected. See #306