src/vs/editor/common/model/textModel.ts/DecorationsTrees/collectNodesPostOrder
class DecorationsTrees:	public collectNodesPostOrder(): IntervalNode[] {
		const r0 = this._decorationsTree0.collectNodesPostOrder();
		const r1 = this._decorationsTree1.collectNodesPostOrder();
		const r2 = this._injectedTextDecorationsTree.collectNodesPostOrder();
		return r0.concat(r1).concat(r2);
	}