(WASHINGTON) - Senator Raphael Warnock, D-Ga, is calling for Democrats to investigate officials who he says have "manipulated their maps to silence the voices of Black voters," as soon as they flip the House or Senate in the midterms. In the plan, first reviewed by ABC News, Warnock said, "Here is what Democrats must do as soon as we regain power: investigate craven politicians, ban partisan gerrymandering, stop billionaires from buying our elec…