Regenerate man pages with docutils 0.16

Regenerate man pages with docutils 0.16

Commit bdb777b2a2e079ce25f567a316e74436f0584029 updated the man pages
to contents produced using:

  - Sphinx 4.0.2
  - sphinx-rtd-theme 0.5.2
  - docutils 0.17.1

However, sphinx-rtd-theme 0.5.2 is incompatible with versions 0.17+ of
the docutils package.  This problem was addressed in the Docker image
used for building man pages by downgrading the docutils package to
version 0.16.

Regenerate the man pages again, this time using:

  - Sphinx 4.0.2
  - sphinx-rtd-theme 0.5.2
  - docutils 0.16

This is necessary to prevent the "docs" GitLab CI job from failing.