src/vs/editor/contrib/documentSymbols/browser/outlineModel.ts/OutlineModel/updateMarker
class OutlineModel:	updateMarker(marker: IOutlineMarker[]): void {
		// sort markers by start range so that we can use
		// outline element starts for quicker look up
		marker.sort(Range.compareRangesUsingStarts);

		for (const [, group] of this._groups) {
			group.updateMarker(marker.slice(0));
		}
	}