Editor’s note: CNN Films brings the premiere of “Super/Man: The Christopher Reeve Story” to CNN at 8 p.m. ET/PT Sunday. CNN  —  Dana Reeve was devoted to caring for her husband, Christopher Reeve, as noted in the new documentary “Super/Man: The Christopher Reeve Story.” In her diary, Dana expressed a part of her experience that caregivers often hesitate to say out loud, as read by her son, Will, in the documentary. “I’ve been studying the difference between solitude and loneliness, telling the