PERCY ZVOMUYA The dub poet Linton Kwesi Johnson, this year’s recipient of the PEN Pinter Prize, is the third consecutive black winner of the gong instituted in memory of Nobel-winning playwright Harold Pinter. Johnson, popularly known as LKJ, follows in the wake of British poet Lemn Sissay (2019) and Nigerian writer Chimamanda Ngozi Adichie (2018).   It’s no exaggeration that LKJ, who went to Britain from Jamaica at the age of 11 to follow his mother, part of the Windrush generation, did more than most to make black “cool” in Britain and beyond. In his music and poetry, he not only…