LONDON — A major British doctors’ group says the U.K. government should “urgently review” its decision to give people a second dose of the Pfizer-BioNTech coronavirus vaccine up to 12 weeks after the first, rather than the shorter gap recommended by the manufacturer and the World Health Organization. The U.K., which has Europe’s deadliest coronavirus outbreak, adopted the policy in order to give as many people as possible a first dose of vaccine quickly.