rebase: skip obsolete commits even if they have pruned successors Issue 5782 reported that `hg rebase -r <obsolete commit with pruned successor>` failed with an error saying that it would cause divergence. Commit b7e2cf114e85 (rebase: do not consider extincts for divergence detection (issue5782), 2018-02-09) fixed it by letting you rebase the commit. However, that fix seems inconsistent with how we handle `hg rebase -r <pruned commit>`. To me, it should make no difference whether a commit is pruned itself or if it has (only) pruned successors. This patch changes it so we treat these two kinds of commits the same way. I let the message we print remain "note: not rebasing <commit>, it has no successor" even though that last part is not technically correct for commits with pruned successors. I doubt it will confuse users. Differential Revision: https://phab.mercurial-scm.org/D10240