Custom finalizer method for diffobj html content finalizing. This method is used to modify the diff html output so that omitted rows have their own special styling and gutters.
my_finalizer(x, x.chr, omit)comparator instance used for the comparison that is meant to be created with the factory method vrf_comparator.
character text representation of x, typically generated with the as character
all lines containing the omit string will be excluded from the comparison (detaulf = NULL)