[SPARK-11860][PYSAPRK][DOCUMENTATION] Invalid argument specification …
[SPARK-11860][PYSAPRK][DOCUMENTATION] Invalid argument specification …

…for registerFunction [Python]

Straightforward change on the python doc

Author: Jeff Zhang <zjffdu@apache.org>

Closes #9901 from zjffdu/SPARK-11860.

(cherry picked from commit b9b6fbe89b6d1a890faa02c1a53bb670a6255362)
Signed-off-by: Sean Owen <291c18f3fb7528c712d9098b0e50a515ea0b91d5@cloudera.com>

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