[w3c/webauthn] a2c99a: Fix list numbering accidentally broken by fc2c7b8

  Branch: refs/heads/issue-644
  Home:   https://github.com/w3c/webauthn
  Commit: a2c99a513ad0b38c9d2cca60951d0384cd51f2e0
      https://github.com/w3c/webauthn/commit/a2c99a513ad0b38c9d2cca60951d0384cd51f2e0
  Author: Emil Lundberg <emil@yubico.com>
  Date:   2017-11-09 (Thu, 09 Nov 2017)

  Changed paths:
    M index.bs

  Log Message:
  -----------
  Fix list numbering accidentally broken by fc2c7b8