Update ds18b20.go

ds18b20/ds18b20.go

@@ -34,7 +34,7 @@ func ConvertAll(o onewire.Bus, maxResolutionBits int) error {
 }
 
 // StartAll starts a conversion on all DS18B20 devices on the bus.
-// Similar to ConvertAll but returns without waiting for converion to finish.
+// Similar to ConvertAll but returns without waiting for conversion to finish.
 // To be used in conjunction with LastTemp() function. Conversion timing must be
 // handled by other means.
 func StartAll(o onewire.Bus) error {