tests/test-gendoc-sv.t

py3: don't index into bytes in phabricator's _tokenize()

`phabread`ing a stack using `hg phabread :D1234` under py3 will currently die
with a KeyError because it will index into `b':D1234'` and return `58` instead
of `b':'` as a token.

Differential Revision: https://phab.mercurial-scm.org/D7129

#require docutils gettext

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