By William Schomberg LONDON (Reuters) -British finance minister Jeremy Hunt said he will have to raise taxes in next week’s budget plan in order to fix the public finances and soften a potentially long recession, a newspaper quoted him as saying on Saturday. Hunt is trying to restore Britain’s credibility among investors in the first budget plan since Rishi Sunak replaced Liz Truss as prime minister last month with a vow to undo her economic policy mistakes, chiefly a series of unfunded tax cuts. Truss’s “mini-budget” in September set off a bond market slump that sent borrowing costs soaring a…