Marry Harry revives a genre not much seen in these parts lately, the charm musical. The work of Jennifer Robbins (book), Dan Martin (music), and Michael Biello (lyrics), the show is small and hasn’t much on its mind, just the urge to put a few likable characters through a simple story and send its audience out with a collective feeling of “Aww.” Thanks to an attractive production on the intimate York Theatre stage and an overqualified cast, it gets its “Aww,” though it also earns a couple of orders of “You can’t be serious.”