Those tools exists already. I used PlantUML[0] at my programming course. UML is nonsense, of course, but it was part of the curriculum, and it was more tolerable doing UML in Vim than in a graphical point-and-click editor.
Eh, uml is a tool. Pretending to document fully or even to have uml as ground truth is a fool errand, of course, but since our daily job involves taming complexity, any system of knowledge partitioning that one can assume everyone else understand is a godsend
[0]: https://plantuml.com/