With his first-ever feature role as the titular, gaping über-nerd lead in “Napoleon Dynamite” (2004), actor Jon Heder became a cult hero overnight – one who would be forever canonized on celluloid and DVD. The film did more than just propel the young actor into celebrity, however – it also galvanized an entire generation of nerds, geeks and dweebs who could relate to being shoved into lockers, playing lonely games of tetherball or having a pocketful of Tater-Tots smashed by the class bully. The rabid fandom that arose from “Napoleon Dynamite” got weird, though, when accounts of Heder’s death –