Update WH6DSN HT1250 code plug, correct two repeaters.

WB1GOF in Westford was entered as Rx 146.995/Tx 146.395.  The correct
frequencies are Rx 146.955/Tx 146.355.

W1NH on Mt. Washington was entered as Rx 146.665/Tx 146.065.  The correct
frequencies are Rx 146.655/Tx 146.055.