Kendall Jenner, Suki Waterhouse and Rihanna have found a shortcut to beating the chill and upgrading their knitwear in one easy move: by chucking on a bigger-the-better flecked knit. With strong Stella McCartney AW14 vibes, the earthy tone (so 70s) and too-long sleeves are the necessary features to get to know. Get schooled in the art of slouchy sweaters by these girls…