logging.py: fix critcal() docstring
logging.py: fix critcal() docstring

critical() output goes to console as well.

Bug: T195537
Change-Id: Ia23832ee70f84e2860400ad0bbd24ecaeaeb1bd3

wikimedia/pywikibot-core,PersianWikipedia/pywikibot-core,wikimedia/pywikibot-core