Long story short, I was sick of writing man pages in an endless cycle of edit-view, edit-view so I decided to do something about it and made this editor. It's a bit rough around the edges, but it works really well for me. Maybe it will also be of some use to you.
To learn more about the macOS man page format, run the following command:
or, alternately, read this page.
You can download a pre-built application here: