NEW YORK — R&B star R. Kelly was sentenced to 30 years in prison Wednesday for using his superstardom to subject young fans — some just children — to systematic sexual abuse.The Chicago singer and songwriter, 55, was convicted of racketeering and sex trafficking last year at a trial that gave voice to accusers who had once wondered if their stories were being ignored because they were Black women.Kelly has been jailed without bail since in 2019. He’s still facing child pornography and …