MITCHELL — Main Street in Mitchell was filled with the smell of barbecue, the shine of polished chrome and steady foot traffic Saturday as the community gathered for a Memorial Day celebration featuring food, competition and a new focus on mental health awareness. Ten teams competed in a barbecue cookoff, more than 75 vehicles lined downtown for a show-and-shine, and a first-time Mental Health Awareness 5K run/walk added a new element to the day…