custom edit text for cardtype-plus-field

We've run into wanting edit text for a field, and wanting it to be different in different contexts, e.g. in Ticket+description we want different edit text from Feature+description. Suggested solution is to use something like Ticket+description+*edit (and +*new). If the left card is a cardtype or a card with a right form, the +*edit (or +*new) text shows up when +description is edited in a Ticket card / right-formatted card).

When done, update help text.