rebase: stop relying on having two parents to resume rebase I'm about to make it so we don't have two parents when a rebase is interrupted (unless we're just rebasing on a merge commit). The code for detecting if we're resuming a rebase relied on having two parents, so this patch rewrites that to instead set a boolean when we resume. Note that `self.resume` in the new condition implies `not self.inmemory` (rebase cannot be resumed in memory), so that's why that part can be omitted. Differential Revision: https://phab.mercurial-scm.org/D7826

graphlog: use '%' for other context in merge conflict This lets the user more easily find the commit that is involved in the conflict, such as the source of `hg update -m` or the commit being grafted by `hg graft`. Differential Revision: https://phab.mercurial-scm.org/D8043

tests: add `hg log -G` output when there are merge conflicts The next commit will change the behavior for these. I've used slightly different commands in the different tests to match the surrounding style. Differential Revision: https://phab.mercurial-scm.org/D8042