“The Velveteen Rabbit” is a deeply magical story. But its magic resides not in fairy-tale occurrences — although there are those, as when a love-worn stuffed rabbit is transformed into a real, hopping bunny. The story carries the magic of nostalgia. It is a celebration of the kind of bond that can span generations, of love that can grow with children as they journey toward adulthood. This year marks the beginning of the 31st season of ODC/Dance’s holiday performance of “The Velveteen Rabbit,” the company’s beloved tradition that returns Saturday, Nov.