Preview next due interval

To some users, especially incremental readers, knowing the next due interval corresponding to the choices might be helpful for planning the next review time.

Idk if its possible for FSRS, but could the reviewing interface display the estimated next due time?

[oflg]

It's OK. I have thought about this function and reserved the interface for the next due date.

[oflg]

This will be achieved with the new FSRS algorithm (oflg/TiddlyMemo#24)