The build of kernel-docs package fails on TW with the recent Sphinx package:
  Could not import extension kerneldoc (exception: cannot import name
'Directive')
  make[2]: *** [../Documentation/Makefile:68: htmldocs] Error 2

It's due to the import of Directive in Documentation/sphinx/kerneldoc.py:
  from sphinx.util.compat import Directive

where it was deprecated in the recent version.
The fallback to the following is needed:
  from docutils.parsers.rst import directives, Directive