demandoc(1)

From: Graham Perrin <grahamperrin_at_freebsd.org>
Date: Sun, 06 Aug 2023 01:34:30 UTC
<https://mandoc.bsd.lv/man/demandoc.1.html>

Added in 2014, removed in 2015:

<https://github.com/freebsd/freebsd-src/commit/2421b90f47750cb634efef703c5f88b3d30b2ee1>
<https://github.com/freebsd/freebsd-src/commit/7b0896d8828c4bad9ed1190da5f6204a349231f3>

I added what was removed, but it didn't build.

How difficult would it be to have demandoc in base, again?

For now: I installed from source, ignoring a conflict with 
/usr/local/bin/soelim, then reinstalled groff.