Trump supporters chanted “Lock her up!” Saturday when the president ranted about Michigan Gov. Gretchen Whitmer at a rally just 10 days after white supremacists were busted for a kidnapping plot targeting her.At a rally in Muskegon, Michigan, President Donald Trump grinned as the #MAGA throng ate up his denunciations of Whitmer over the restrictions she imposed to limit the spread of coronavirus in the hard-hit state.“You gotta get your governor to open up your state,” Trump told thousands of cheering backers.That’s when the crowd started chanting, “Lock her up!”The president made no effort to…