By Steve Holland WASHINGTON (Reuters) -U.S. President Joe Biden’s campaign trail promise to increase taxes on corporations and the wealthy as part of a battle against glaring income inequality in the United States got an unexpected boost on Wednesday. Early proposals to increase tax rates from Biden and his fellow Democrats hit a brick wall in Congress after Republicans — and some Democrats — opposed them. But a sudden reversal by West Virginia Democratic Senator Joe Manchin, a swing vote in the divided Senate, has given Biden’s tax agenda a new lease on life. The amount U.S. companies contr…