Add info about diagrams.net saving to GitHub
@@ -2,3 +2,6 @@ The sources for the vector diagrams (in `xml/`) can be edited with
[diagrams.net](https://app.diagrams.net/) - formerly called "draw.io".
The SVG files in `svg/` are exported versions of those.
+
+Note that diagrams.net allows you to directly save and export the files
+to your cocotb fork/branch on GitHub, producing git commits.
