cleanup: prefer nested context managers to \-continuations I'd prefer Python accept a tuple of context managers, but alas it isn't meant to be. This will have to suffice. Differential Revision: https://phab.mercurial-scm.org/D5994

cleanup: use () to wrap long lines instead of \ This is a little less brittle, and often helps indentation. In a surprising number of cases the entire cleanup was deleting the \, as the expression was *already* parenthesized in a workable way. Differential Revision: https://phab.mercurial-scm.org/D5993

tests: use () instead of \ to wrap lines This should auto-format more consistently, and is slightly more typical Python. Differential Revision: https://phab.mercurial-scm.org/D5992