cleanupnodes: trust caller when "moves" is not None
If "moves" (indicating how to move bookmarks) is None, we fill it out
based on "replacements" (indicating which obsmarkers to add). If
"moves" is not None, we would still add items based on
"replacements". This makes it impossible to pass "moves={}" and not
move bookmarks, which surprised me. The only caller that currently
passes a value for "moves" was the rebase extension and there we were
already adding bookmark moves corresponding to obsmarker additions, so
it should not be impacted.
Differential Revision: https://phab.mercurial-scm.org/D5391
#require docutils gettext
$ $TESTDIR/check-gendoc ru
checking for parse errors