Anton Shestakov <av6@dwimlabs.net> [Sat, 29 Jun 2019 18:21:57 +0800] rev 4699
prune: update to the successor of wdir also with --pair/--biject (issue6142)
When prune is used with --pair flag, we can also update to the successor of
working directory parent.
No need to check len(sucs) or len(precs) here because there's a check for that
earlier in the code (it's a requirement of biject).
The tests are now demonstrate the correct behavior: when rev 14 was pruned with
12 as its successor, the bookmark that was on 14 was moved to 12. That bookmark
was also activated (even before this patch).