packaging: add docutils as dependency
The previous commit revealed that attempting to run
`python setup.py build_doc` from the packaging virtualenv
failed due to missing docutils package. We didn't notice
this before because py2exe Windows packaging appears to
use a Python from another virtualenv (which does include
docutils) to invoke setup.py. I discovered this as part
of implementing packaging outside of that virtualenv
environment.
Differential Revision: https://phab.mercurial-scm.org/D8470
#require emacs
$ emacs -q -no-site-file -batch -l $TESTDIR/../contrib/hg-test-mode.el \
> -f ert-run-tests-batch-and-exit
Running 1 tests (*) (glob)
passed 1/1 hg-test-mode--compilation-mode-support
Ran 1 tests, 1 results as expected (*) (glob)