Sure, you've all heard of matching your sweater to your trousers, your shoes to your dress, but have you ever heard of matching your bag to your coat? It seems simple enough, but it's only recently that we've truly considered the styling trick. Suffice to say, once we dipped our toe in the bag-and-coat-pairing pool, we couldn't help but dive in, head first. Clutches, totes, and satchels abound, styled with everything from a duster coat to a cropped jacket: This is the cold-weather trend you…