Hello,

We at RGBDS[https://rgbds.gbdev.io] use Mandoc for our manual pages, as well as the online documentation. I happened to notice that the "At-files" anchor under "REVERSE MODE"[https://rgbds.gbdev.io/docs/master/rgbgfx.1#REVERSE_MODE] does not work, as it points to #At_files instead of #At-files.

While we do some post-processing[https://github.com/gbdev/rgbds-www/blob/master/maintainer/man_to_html.sh], none of it should affect this, as far as I'm aware, therefore I think it is a Mandoc bug. Sorry if I'm wrong on that.

Thank you for your continued efforts!
~ Eldred