[webauthn] Pull Request: Fix #574 - Change language for Create and Get to support hotplugging

jcjones has just submitted a new pull request for https://github.com/w3c/webauthn:

== Fix #574 - Change language for Create and Get to support hotplugging ==
This is an incomplete fix; a full fix is intended to be handled in Issue #613.

This reorders the Create and Get operations to indicate that the algorithms for
interacting with devices should be applied as devices are hotplugged / arrive.
It does not specify what happens when devices are removed, nor does it use
precise language. I'm not sure what language would be appropriate in this world,
so this patch is just to make things "better" not "correct".

See https://github.com/w3c/webauthn/pull/655