This is CNBC's Morning Squawk newsletter. Subscribe here to receive future editions in your inbox. Happy start to a short week. Stocks are slightly higher, Greg Abel is a U.S. citizen and the U.S. is prepping for a scorcher for the holiday — with air conditioning. Here are five key things investors need to know to start the trading day: Spinoffs: They're not just for industrials . Comcast is planning to spin off its media and technology businesses into two publicly traded companies through a