If you like Broadway musicals featuring catchy songs, colorful dance numbers and a hilarious storyline with just the right hint of darkness, then the Sharon High School Theatre Company has just the show for you."Thoroughly Modern Millie," which debuted at Sharon High School last night and runs through the weekend, tells the story of a small-town girl, Millie, who arrives in New York City during the Roaring Twenties with dreams of finding a richhusband. After checking into a women's hotel that has more than a few secrets to tell, Millie meets a whacky assortment of guys and dolls, all of whom …