tests/test-gendoc-fr.t

rename: add support for --at-rev, which marks as copy and removes the source

I had previously only added support for `--at-rev` to `hg cp`, but not
to `hg mv`. This patch adds that support. Just like for `hg cp`, it
marks the destination as copied from the source, and doesn't care if
the source file still exists (because it only supports the `-A` mode,
aka "don't touch files" mode). It works whether or not the source file
still exists. This matches the behavior of `hg mv -A` in the working
copy.

Differential Revision: https://phab.mercurial-scm.org/D8840

#require docutils gettext

  $ $TESTDIR/check-gendoc fr
  checking for parse errors