[w3c/webauthn] 6d5aa3: Address review comments by @kieun (#832)

  Branch: refs/heads/master
  Home:   https://github.com/w3c/webauthn
  Commit: 6d5aa3e58d23a710b8756289c63bc00f69190baa
      https://github.com/w3c/webauthn/commit/6d5aa3e58d23a710b8756289c63bc00f69190baa
  Author: Emil Lundberg <emil@emlun.se>
  Date:   2018-04-11 (Wed, 11 Apr 2018)

  Changed paths:
    M index.bs

  Log Message:
  -----------
  Address review comments by @kieun (#832)

* Address review comments by @kieun

* Revert CTAP2 URL fragment change

See comment by @equalsJeffH at
https://github.com/w3c/webauthn/pull/832#discussion_r173599006

* <dfn> AppID in FIDO AppID Extension section heading

As suggested by @equalsJeffH at
https://github.com/w3c/webauthn/pull/832#discussion_r173599568