Fix of typos in documentation of pyspark.sql.functions and output of lint-python

Minor documentation and standard output issues:

• dev/lint-python contains a typo when printing a warning regarding bad Sphinx version ("lower then 3.1" rather than "lower than 3.1")
• The documentations of the functions lag and lead of pyspark.sql.functions refer to a parameter defaultValue, which in reality is named default.
• The documentation strings of functions in pyspark.sql.functions make reference to the Column class, which is not resolved by Sphinx unless fully qualified as pyspark.sql.Column