Issue #2734983 by Nikhilesh Gupta, neerajsingh, dimaro, mayurjadhav: Remove deprecated SafeMarkup::checkPlain usages from core

Issue #2611638 by Wim Leers, Nikhilesh Gupta: hook_entity_query_alter() is dead, remove it from entity.api.php

Issue #2611044 by felribeiro, theMusician, Nikhilesh Gupta, cilefen: SystemInfoController::status - wrong documentation (follow-up to fix whitespace)

Issue #2611044 by felribeiro, theMusician, Nikhilesh Gupta, cilefen: SystemInfoController::status - wrong documentation