Thanks for querying this! For short patches, I actually quite like them just pasted into the issue or comment text in the tracker, surrounded by the Markdown triple-backquotes for code formatting.
However I probably should set up a list as well, it would make more sense for longer patches and back-and-forth. I've only relatively recently started doing serious work with this platform, so I'm still gradually figuring out a sensible approach. I'll leave this issue open as a reminder - not just to decide on this but also to document it.