Dell Technologies Inc. has reorganized some of its leadership, putting Chief Operating Officer Jeff Clarke directly in charge of its personal computer unit amid a prolonged slump in that business.Clarke, who joined Dell in 1987 and is also vice chair, will oversee the company’s Client Solutions Group, according to a memo to the staff seen by Bloomberg and confirmed by Dell. The unit, which includes desktop and notebook computers for corporate clients and consumers, had been run by Sam Burd....