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).
syntax: re
/figures/[^/]+\.png$
^html/
\.pyc$
~$
\.swp$
\.orig$
\.rej$
^tests/.*\.err$
^tests/easy_run.sh$
^build/
^dist/
^MANIFEST$
^docs/tutorials/.*\.rst$
\.ico$
tests/\.testtimes
^docs/training/graphs/
^docs/training/html/
^docs/training/index.html
^docs/training/graphviz-images/
^docs/training/img/
^docs/training/output/
^docs/training/pandocfilters/