Update doc reference to PhabricatorIRCBot for D4757
Summary: Update doc reference to PhabricatorIRCBot for D4757
Test Plan: Read the docs
Reviewers: indiefan, epriestley, #blessed_reviewers
Reviewed By: epriestley, #blessed_reviewers
Subscribers: Korvin, epriestley
Differential Revision: https://secure.phabricator.com/D11098