People who lived in New York in the 1970s and ’80s are always cautioning against over-romanticizing the era: a dirt-cheap apartment often meant living with a bathtub sprouting from the middle of your kitchen, or having to step around junkies on your doorstep. You could be mugged at any hour of the day or night. But who could be blamed for wanting to live in the New York of Ira Sachs ’ Peter Hujar’s Day, a 76-minute movie that feels quiet and modest while you’re watching it, only to fill the air