AsciiDoctor has GraphViz (and PlantUML plus a few more) available inline (it handles the conversion for you). The syntax has a few differences to Markdown but i

AsciiDoctor has GraphViz (and PlantUML plus a few more) available inline (it handles the conversion for you). The syntax has a few differences to Markdown but it's not too hard to adapt plus it has a few other awesome features that I always miss when in Markdown.