tests: demonstrate prune --pair not moving bookmark correctly After `mkcommit n2` line the bookmark is on the correct changeset, but when we prune --pair the two newly created changesets (revs 13 and 14), the bookmark gets moved to their ancestor (rev 0). Instead, it should've moved to the last of their successors (rev 12).

{"site_id":"cf023865-0eb1-49e9-951b-29555949abf0","path":"html/"}