fix(dataFrameShow): Remove extra new lines

[tools4origins]

A regression was introduced in the latest commit on master:

spark.range(3).show() printed not wanted blank lines:

+---+
| id|
+---+
|  0|
<BLANK LINE>
|  1|
<BLANK LINE>
|  2|
<BLANK LINE>
+---+

This went unnoticed because doctest was configure to ignore whitespace differences, which we do not want for instance because of this regression, hence the removal in setup.cfg

[tools4origins]

This PR which only modifies two lines fails on an unrelated issue because there was a modification of an external library (isort).

It's again an example of the issue mentioned in #157 (comment)

The solution would be to align the code with a recent version of isort and fix this version in the requirements (this is done in #157)