By ALISSA WILKINSON When the idiosyncratic and hilarious HBO show “How To With John Wilson” ended in 2023, its eponymous creator found himself at loose ends. “The space between projects is hard,” he says at the start of “The History of Concrete” (in theaters). “Time becomes unstructured. You settle into some of your worst habits.” And that, in his typically roundabout way, is how he ended up making a documentary about concrete. It’s not just about concrete, as any “How To” fan might have…
