Add blank line so that Python RDD.top() docstring renders correctly

Author: rnowling

python/pyspark/rdd.py

@@ -1060,6 +1060,7 @@ def top(self, num, key=None):
         Get the top N elements from a RDD.
 
         Note: It returns the list sorted in descending order.
+
         >>> sc.parallelize([10, 4, 2, 12, 3]).top(1)
         [12]
         >>> sc.parallelize([2, 3, 4, 5, 6], 2).top(2)