src/vs/workbench/contrib/mergeEditor/browser/model/rangeUtils.ts/addLength
export function addLength(position: Position, length: LengthObj): Position {
	if (length.lineCount === 0) {
		return new Position(position.lineNumber, position.column + length.columnCount);
	} else {
		return new Position(position.lineNumber + length.lineCount, length.columnCount + 1);
	}
}