[PYTHON] Fixed typo in exception message

Just fixing a typo in exception message, raised when attempting to pickle SparkContext.

Author: Icaro Medeiros <icaro.medeiros@gmail.com>

Closes #8724 from icaromedeiros/master.

python/pyspark/context.py

@@ -255,7 +255,7 @@ class SparkContext(object):
         # This method is called when attempting to pickle SparkContext, which is always an error:
         raise Exception(
             "It appears that you are attempting to reference SparkContext from a broadcast "
-            "variable, action, or transforamtion. SparkContext can only be used on the driver, "
+            "variable, action, or transformation. SparkContext can only be used on the driver, "
             "not in code that it run on workers. For more information, see SPARK-5063."
         )