Eclipse and IntelliJ IDEA have both functions, so they might fit together in one package; alternatively, I think you might need to fork and modify this plugin for your goal.

To me, the interesting question is how to add this feature; the plugin should listen on events for arbitrary text changes to record the solution. However, I cannot even find the list of all accessible events in the Atom docs, and the source is not so helpful yet.

Overall, what’s the event the plugin should listen on to get notified of all edits?