setPrintTitleRows method
Repeats rows fromRow-toRow (0-based, inclusive) at the top of every
printed page. Preserves any repeating columns already set.
Implementation
void setPrintTitleRows(int fromRow, int toRow) => _setPrintTitles(
rowsRef: '$_quotedSheetName!\$${fromRow + 1}:\$${toRow + 1}',
);