[groff] Announcement and call for project submissions

[John Gardner]

I've created a Homebrew "tap" <https://docs.brew.sh/Taps> for *roff or
man-related ports and packages which can be easily installed on macOS using
Homebrew:

https://github.com/Alhadis/homebrew-troff


My attempt to submit man-db to Homebrew's core package registry didn't go
as planned, which is a polite understatement. I'll not waste time griping;
those curious can find the thread's nadir here
<https://github.com/Homebrew/homebrew-core/pull/36469#issuecomment-458474772>
.

I've already added a formulae for Heirloom Doctools, and plan on adding one
for Neatroff too. I hope to add @n-t-roff <https://github.com/n-t-roff>'s
historical Troff ports, as well as any investigate the possibility of
distributing `tmac` files through Homebrew. E.g., running `brew install
mdn.tmac` would place `dn.tamc` in one's tmac path.

If anybody knows of any package or ports they'd like to share, please do!
It doesn't matter if they're modern or historical codebases, it'll be great
to get as much Troff-related utilities out there. :D