src/vs/editor/common/model/bracketPairsTextModelPart/bracketPairsTree/length.ts/LengthObj/add
class LengthObj:	public add(other: LengthObj): LengthObj {
		if (other.lineCount === 0) {
			return new LengthObj(this.lineCount, this.columnCount + other.columnCount);
		} else {
			return new LengthObj(this.lineCount + other.lineCount, other.columnCount);
		}
	}