Roku Inc (NASDAQ:ROKU) stock is on the rise, up 2.3% at $111.59 at last check, after a rare double upgrade from Morgan Stanley to "overweight" from "underweight," to go with a price-target hike to$135 from $85. The firm cited multiple tailwinds, including faster revenue growth, and expects a strong year ahead for the advertising industry. On the charts, Roku stock has been rallying since the start of the month, and could soon overtake its Oct. 31 three-year high of$116.66. During this rally, short interes ...