histedit: more precise user message when changeset is missing Now that we explicitly detect duplicated changesets, we can explicitly detect missing ones. We cover the same cases as before, some others and we offer a better error message in all cases.

histedit: protect against duplicated entries Before this change one would issue rules with duplicated entries. For this to happen some other changeset had to be missing to maintain the rules length.

histedit: track short hash instead of changectx object This simplifies set usage and allow us to add a missing revision check in a later commit.