src/vs/editor/contrib/folding/browser/foldingRanges.ts/FoldingRegions/setCollapsedAllOfType
class FoldingRegions:	public setCollapsedAllOfType(type: string, newState: boolean) {
		let hasChanged = false;
		if (this._types) {
			for (let i = 0; i < this._types.length; i++) {
				if (this._types[i] === type) {
					this.setCollapsed(i, newState);
					hasChanged = true;
				}
			}
		}
		return hasChanged;
	}