DETROIT -- Pete Buttigieg, who entered the Democratic presidential race as a relative unknown and positioned himself as the future of the party during an improbable rise to the top tier of a crowded field, ended his White House bid on Sunday.Buttigieg, 38, a former two-term mayor of South Bend, Indiana, an Afghanistan war veteran and the first openly gay candidate to make a competitive run for the US presidency, narrowly won the Iowa caucuses that kicked off the nominating race in February and