This isn't a very good solution, IMHO. Or, it doesn't scale. If you find yourself with an existing solution that doesn't scale for what you need it to, cut your losses and find a better tool or solution.

Some simple visualization using ASCII is fine. Something you can create from scratch and otherwise modify in as much time as it would take to document code. But, if you need a sequence diagram, or flow chart, what not. The tradeoff for maintenance and lack of readability makes it look silly. The "why was this developer wasting time doing things with the wrong tools"-kind of silly.

If you need complex diagrams. Create them using draw.io or plantuml, and add them to the source control. Generate images which you instead reference in the documentation in code. Tools such as Doxygen and other such tools would be able to pull in the images and actually look good. This is both maintainable, and scalable.