Pywikibot: Add documentation generation to deprecation decorator
See https://phabricator.wikimedia.org/T121366
Improve the Pywikibot documentation of deprecated functions by updating the @deprecated decorator to automatically add deprecation information to the docstrings of deprecated functions.
Pywikibot is a Python-based framework to write bots for MediaWiki. See https://www.mediawiki.org/wiki/Manual:Pywikibot for more information. See https://www.mediawiki.org/wiki/User:John_Vandenberg/GCI_walk-through for a short introduction to using Pywikibot. Patches can be submitted via Gerrit (you need a MediaWiki.org account). See https://www.mediawiki.org/wiki/Manual:Pywikibot/Gerrit. After you have successfully claimed this task on this site please do use the task in Phabricator for communication instead. This allows more PWB developers to be reached! General development questions can be asked on the Pywikibot mailing list at https://lists.wikimedia.org/mailman/listinfo/pywikipedia-l and the #pywikibot IRC channel (see https://www.mediawiki.org/wiki/MediaWiki_on_IRC ).