[DOCS] Fix typo for Python section on unifying Kafka streams
[DOCS] Fix typo for Python section on unifying Kafka streams

1) kafkaStreams is a list.  The list should be unpacked when passing it into the streaming context union method, which accepts a variable number of streams.
2) print() should be pprint() for pyspark.

This contribution is my original work, and I license the work to the project under the project's open source license.

Author: chriskang90 <jckang@uchicago.edu>

Closes #9545 from c-kang/streaming_python_typo.

(cherry picked from commit 874cd66d4b6d156d0ef112a3d0f3bc5683c6a0ec)
Signed-off-by: Sean Owen <291c18f3fb7528c712d9098b0e50a515ea0b91d5@cloudera.com>

haowu80s/spark,haowu80s/spark,haowu80s/spark,haowu80s/spark,haowu80s/spark,haowu80s/spark