(Reuters) - European shares gained slightly on Wednesday, helped by bank stocks following strong results from Santander, but mounting concerns about the fast-spreading coronavirus kept a lid on gains.By 0809 GMT, the pan-European STOXX 600 rose 0.1%, continuing a recovery from a selloff earlier this week. Spain's IBEX outperformed regional bourses, lifted by a 2% rise in Santander . The lender posted a higher quarterly net profit, boosted by a solid underlying performance in its main market..