merge method

Implementation

DividerThemeData merge(DividerThemeData? style) {
  if (style == null) return this;
  return DividerThemeData(
    decoration: style.decoration ?? decoration,
    thickness: style.thickness ?? thickness,
    horizontalMargin: style.horizontalMargin ?? horizontalMargin,
    verticalMargin: style.verticalMargin ?? verticalMargin,
  );
}