This request is inspired after gitLab plantUML support.

PlantUML is a great tool for diagrams and UML design that truly completes a wiki platform. I personally prefer it over tools like gliffy because of the versioning tracking possible thanks to its easy plain text language similar to programming code. It is a perfect addition to Wiki.js.

PlantUML official site

http://plantuml.com/

gitLab PlantUML reference

https://docs.gitlab.com/ee/administration/integration/plantuml.html