check-code: stop forbidding return code result There is no explication of what is the intend of that check and what is the alternative. I suspect this comes from the transition to the "unified test" format circa 2010. With the non zero return explicitly listed in the output explicit $? checking became Redundant. However there is valid use case for checking $? so I am dropping this check. Differential Revision: https://phab.mercurial-scm.org/D10994