Hedge fund Greenlight Capital, managed by David Einhorn, lashed out at several companies in its letter to investors late Tuesday, but Greenlight and Einhorn got personal with Tesla Inc. TSLA, -0.47% According to the letter, Einhorn "is happy that his Model S lease ended (there were growing problems with the touchscreen and the power windows" and happy to switch to an electric Jaguar. Next year will be "a very challenging" year for Tesla, and the letter continued on a more personal tone saying that Tesla Chief Executive Elon Musk "appears erratic and desperate." Replying to a tweet about Einhorn's lapsed …