The delisting of China stocks in the US quickened as Didi announced its exit and the US finalized rules to enforce audits on Chinese firms. China ride-hailing giant Didi Global’s shares plunged more than 22% in the US on Friday, losing about $8.4 billion in market value, to end a week in which the decoupling of the equity markets of the world’s two biggest economies gathered pace. The plunge followed Didi’s announcement that it planned to delist from the New York Stock Exchange less than six months after its bumper $4.4 billion IPO there. Didi’s decision followed China’s swinging crackdown…