src/vs/workbench/contrib/comments/browser/commentService.ts/CommentService/getCommentingRanges
class CommentService:	async getCommentingRanges(resource: URI): Promise<IRange[]> {
		let commentControlResult: Promise<IRange[]>[] = [];

		this._commentControls.forEach(control => {
			commentControlResult.push(control.getCommentingRanges(resource, CancellationToken.None));
		});

		let ret = await Promise.all(commentControlResult);
		return ret.reduce((prev, curr) => { prev.push(...curr); return prev; }, []);
	}