By Tom Balmforth and Vladyslav Smilianets KYIV/NEAR BAKHMUT, Ukraine (Reuters) -The battle for the eastern Ukrainian salt mining town raged in sub-zero temperatures on Wednesday, as Russia’s mercenary Wagner Group claimed it had taken control, with its fighters training their fire on a pocket of resistance in the town centre. Kyiv said earlier its forces were holding out. The Ukrainian military’s morning summary made one mention of Soledar, listing the town as one of several being shelled in the Donetsk region. Reuters was unable to verify conditions on the ground. Russian commanders have made…