py-pyobjc: install fails when running Sphinx

[laughingtiger]

When installing Certbot under macOS 12.0.1 (Mac mini (Late 2014)) the py39-pyobjc install fails with this...

:info:build Installing 'pyobjc-framework-libdispatch' using '/opt/local/Library/Frameworks/Python.framework/Versions/3.9/bin/python3.9'
:debug:build Executing proc-post-org.macports.build-build-0
:debug:build system -W /opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_python_py-pyobjc/py39-pyobjc/work/pyobjc-7.3/docs: make -j4 html
:info:build sphinx-build-3.9 -b html -d _build/doctrees . _build/html
:info:build Running Sphinx v4.2.0
:info:build WARNING: while setting up extension sphinx.addnodes: node class 'meta' is already registered, its visitors will be overridden
:info:build Extension error:
:info:build Could not import extension sphinx.directives.patches (exception: cannot import name 'html' from 'docutils.parsers.rst.directives' (/opt/local/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages/docutils/parsers/rst/directives/__init__.py))
:info:build make: *** [html] Error 2
:info:build Command failed: make -j4 html
:info:build Exit code: 2
:error:build Failed to build py39-pyobjc: command execution failed
:debug:build Error code: NONE
:debug:build Backtrace: command execution failed
:debug:build     while executing
:debug:build "$post $targetname"
:error:build See /opt/local/var/macports/logs/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_python_py-pyobjc/py39-pyobjc/main.log for details.