Reword the questions of a draft, or set its rescan cadence

questions is the list of the ones to KEEP with the text to ask, an omitted text keeping the current one; a question of the scan left out of the list is removed, and estimated_cost_minor follows it. rescan_cadence set to weekly or monthly runs the scan again on that cadence, null stops it: it states a state, and replays safely both ways.