bpo-29453: Remove reference to undefined dictionary ordering in Tutorial (GH-140...

bpo-29453: Remove reference to undefined dictionary ordering in Tutorial (GH-140) (#208)

As of Python 3.6 **kwargs are ordered, thus, remove the paragraph stating that
ordering is undefined and change snippet to remove the unecessary sorted call.

* Add sentence mentioning guaranteed output order of kwargs

(cherry picked from commit 32e8f9bdfd4324f1aa4fbbdf1ed8536f2b00cabb)