censor: make rhg fall back to python when encountering a censored node
This is to make it support censor.policy=ignore without having
to duplicate that logic.
Also, change the censor test in such a way that it uses rhg now,
because extensions are disabled except when we call [hg censor].
Differential Revision: https://phab.mercurial-scm.org/D12607
#require docutils gettext
$ $TESTDIR/check-gendoc de
checking for parse errors
Die Dateien werden dem Projektarchiv beim n\xc3\xa4chsten \xc3\x9cbernehmen (commit) hinzugef\xc3\xbcgt. Um dies vorher r\xc3\xbcckg\xc3\xa4ngig zu machen, siehe:hg:`forget`. (esc)
warning: please have a space before :hg: