Discovery Channel joins Alda’s ‘Clear+Vivid’ cast
By GREGORY ZELLER // Decades after “M*A*S*H” and “The West Wing,” screen legend Alan Alda is still crystal clear about his vivid societal mission, which has always combined the entertaining and the enlightening. It’s clear in Alda’s best-known characters, who invariably cut their dry-martini wit with more than a dash of social commentary. And it’s certainly true of “Clear+Vivid,” Alda’s popular podcast, which explores the art of human communication with the veteran performer’s signature depth…