Trenton detectives from a crime suppression unit came upon a surprising sight Monday evening: a man standing on a South Trenton street with an assault rifle hanging from his shoulder. Police spokeswoman Lt. Lisette Rios said the officers detained the man within moments and without incident shortly after 5 p.m. on Turpin Street. They later charged Joseph Moore, 38, with five firearm possession felonies, including firing the weapon. As the detectives were still on scene with Moore in custody, police 911 dispatchers informed them they’d received several calls reporting shots fired in the area, Ri…