[SPARK-19584][SS][DOCS] update structured streaming documentation around batch mode

## What changes were proposed in this pull request?

Revision to structured-streaming-kafka-integration.md to reflect new Batch query specification and options.

zsxwing tdas

Please review http://spark.apache.org/contributing.html before opening a pull request.

Author: Tyson Condie <tcondie@gmail.com>

Closes #16918 from tcondie/kafka-docs.