By Alexander Marrow MOSCOW (Reuters) -Russia’s central bank held its key interest rate at 7.5% at its final meeting of the year on Friday but slightly shifted its rhetoric to acknowledge growing inflation risks, saying a recent military mobilisation was adding to labour shortages. “We gave a neutral signal. This means the next decision, the trajectory of the rate, will depend on the incoming data, on which factors – pro-inflationary or disinflationary – will prevail,” Governor Elvira Nabiullina told a news conference. “In our opinion, pro-inflationary factors prevail now, not only over the med…