Used by the routine at SPECIAL_QUOTE.

Reached from SPECIAL_QUOTE at the opening quote of something said to a character -- SAY TO THORIN "CARRY ME". What follows, up to the closing quote, is parsed as commands of its own, in fresh command frames: this keeps D and COMMAND_FRAMES aside in the two bytes after PLOT_INK, and IY on the stack, steps IY on a frame, and goes back into PARSE_COMMAND at PARSE_ORDER with A = 1, which marks the commands as an order (IS_ORDER).