Broadway play Punch’s excellent, visceral title is also the dark heart of the true story that inspired its making. In 2011, Jacob Dunne, then 19, killed trainee paramedic James Hodgkinson, 28, with a single punch while out drunk one night in the English city of Nottingham. Dunne served a 14-month prison sentence for James’ manslaughter, but his life turned around when James’ parents, Joan Scourfield and David Hodgkinson, reached out to him via a…