The HTML under doc/html was produced by a script kept outside this repository,
so editing a man page and refreshing its HTML were separate manual steps and
the two could drift apart.
Run the same groff conversion in a workflow triggered by a change under man/.
It rebuilds doc/html/index.html and the man5 and man8 pages, and commits only
when something actually changed.
Output was verified byte for byte against the committed tree: all twelve man
pages and index.html are reproduced exactly.
