(Reuters) - Unilever Plc will miss its underlying sales target this year, the consumer goods giant warned on Tuesday, sending shares in the maker of Dove soap and Ben & Jerry's ice cream into their steepest fall in six months.In an unscheduled trading update, Anglo-Dutch Unilever also struck a downbeat tone on its prospects for meeting its mid-term target for sales growth of 3-5% next year."Looking ahead to 2020, growth will be second-half weighted. While we expect improvement in H1 2020..