Document event streams content types

[82marbag]

Hi, nowhere in the docs it is documented to use application/vnd.amazon.eventstream for event streams's content type.

[jjant]

Any updates on this, @mtdowling?

[david-perez]

Worth noting that these sections incorrectly reference application/vnd.amazon.event-stream (note the dash).

• Get the request content-type of an operation
• Get the response content-type of an operation