Google has shown me that are specific devices called snubbers, and also that capacitors can act like a snubber. Would i just a cap on the AC side of the rectifier?
A snubber limits dV/dT. Usually it includes a capacitor and low valued resistor in series but in this case the resistor can be left out.
A low value film or ceramic capacitor, 0.01uF, 0.1uF, whatever, on the AC side of the rectifier but very close to it may be sufficient. Alternatively, smaller capacitors across each diode will work; 10s to 100s of picofarads typically work well. I have also seen EMI suppression beads added to each diode to accomplish the same thing; the added inductance of the beads limits the rate of change in current as the diode recovers.