By Nandita Bose and Andrea Shalal NUSA DUA, Indonesia/WASHINGTON (Reuters) -As midterm election forecasts darkened for his Democratic party, U.S. President Joe Biden kept predicting things would turn around. This weekend, he was partially vindicated as Democrats retained control of the U.S. Senate, bucking history, media projections and pundits who warned voters cared more about gas prices than Biden’s warnings that equality and democracy were under threat. “I know I’m a cockeyed optimist,” Biden told reporters in Cambodia, referencing a sunny song from the musical South Pacific, “but I’m not …