tests/test-gendoc-zh_CN.t

ui: use bytes IO and convert EOL manually in ui.editor()

Text IO sucks on Python 3 as it must be a unicode stream. We could introduce
a wrapper that converts unicode back to bytes, but it wouldn't be simple to
handle offsets transparently from/to underlying IOBase API.

Fortunately, we don't need to process huge text files, so let's stick to
bytes IO and convert EOL in memory.

#require docutils gettext

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