[GNC] Enhancement: Future sched txn update if updated template.

[David G. Pickett]

I schedule my periodic transactions a year in advance, but with constant inflation, often the amount goes up.  It'd be nice to have a way to, by interactive option after I update the template, have gnucash update the already generated future transactions to match an updated template transaction, so I do not need to update 11 or 12 more places.