Add recurring option of “x days after completion.”

Currently there is an option to have a recurring task repeat every x days. But sometimes you have to delay that task and you don’t want the next task to be shorter than x days away.

Example

Buy groceries - recurs every 7 days after completion and this starts in 4/1.

If I buy groceries on 4/1, the next recurrence should be 4/8.

If I failed to buy groceries on 4/1 and it went overdue to 4/2 and I bought groceries on 4/2, then the next recurrence should be 4/9.

The way it currently works is that if I bought groceries in 4/2, the next task will still be 4/8, which is 6 days.