evolution: rename trouble(s) to instability Rename trouble(s) to instability in all external user-facing output. Only update user-facing output for the moment, variables names, templates keyword and potentially configuration would be done in later series. The renaming is done according to https://www.mercurial-scm.org/wiki/CEDVocabulary. Differential Revision: https://phab.mercurial-scm.org/D213