merge method
Implementation
ZeroTextfieldStyle merge(ZeroTextfieldStyle? other) {
if (other == null) return this;
return ZeroTextfieldStyle(
inputDecorationType: other.inputDecorationType,
textfieldSize: other.textfieldSize,
enabled: other.enabled,
error: other.error,
focusedBorderColor: other.focusedBorderColor,
focusedColor: other.focusedColor,
fillColor: other.fillColor,
);
}