[MINOR][DOCS][STRUCTURED STREAMING] Minor doc fixes around `DataFrameWriter` and `DataStreamWriter`

## What changes were proposed in this pull request?

Fixes a couple old references to `DataFrameWriter.startStream` to `DataStreamWriter.start

Author: Burak Yavuz <brkyvz@gmail.com>

Closes #13952 from brkyvz/minor-doc-fix.

1 files changed, 2 insertions, 2 deletions

diff --git a/python/pyspark/sql/dataframe.py b/python/pyspark/sql/dataframe.py
index a2443ed3d6..4f13307820 100644
--- a/python/pyspark/sql/dataframe.py
+++ b/python/pyspark/sql/dataframe.py
@@ -257,8 +257,8 @@ class DataFrame(object):
     def isStreaming(self):
         """Returns true if this :class:`Dataset` contains one or more sources that continuously
         return data as it arrives. A :class:`Dataset` that reads data from a streaming source
-        must be executed as a :class:`StreamingQuery` using the :func:`startStream` method in
-        :class:`DataFrameWriter`.  Methods that return a single answer, (e.g., :func:`count` or
+        must be executed as a :class:`StreamingQuery` using the :func:`start` method in
+        :class:`DataStreamWriter`.  Methods that return a single answer, (e.g., :func:`count` or
         :func:`collect`) will throw an :class:`AnalysisException` when there is a streaming
         source present.