At the top of the PBS documentary “Nureyev: The Russian Years,” which airs on Wednesday, narrator Kenneth Cranham describes Rudolf Nureyev as “the outstanding male dancer of his generation.” It would be more accurate to say that he was perhaps the most influential male dancer of his generation, but he was without a doubt the most highly publicized. This documentary is the latest investigation of a performer who has never been long out of the limelight, even in the 15 years since he died of AIDS. But there is enough new material included here that the wheel is not simply being reinvented; “Nureyev: The Russian Years” adds to the annals of Nureyev scholarship as well as creating a picture of the vanished ballet culture of the Soviet Union.