October was a two-part story for taxable bond investors. Bravery prevailed early in the month. Then jitters set in. The riskiest categories lost ground in most of the final two weeks. But they still ended up topping all taxables for the month. Flexible income funds, which can hold below-investment-grade bonds, led the way, notching a 1.09% October gain, according to preliminary Lipper Inc. data. Emerging markets debt funds were close behind,