Lately, there’s been some low-level public animosity between Wu-Tang figureheads RZA and Raekwon — RZA blaming the lack of a 20th-anniversary reunion album on Rae’s absence, Rae laughing it off. But it’s remarkable how capably Rae carries the spirit of the dark, inward old Wu on his new single “A Rainy Day” — a song [...]