merge method
Copy this with a new ZeroTypography
Implementation
ZeroTypography merge(ZeroTypography? typography) {
if (typography == null) return this;
return copyWith(
heading1: typography.heading1,
heading2: typography.heading2,
heading3: typography.heading3,
heading4: typography.heading4,
heading5: typography.heading5,
heading6: typography.heading6,
subtitle1: typography.subtitle1,
subtitle2: typography.subtitle2,
body1: typography.body1,
body2: typography.body2,
overline: typography.overline,
caption: typography.caption,
);
}