src/vs/editor/contrib/documentSymbols/outlineModel.ts/OutlineModel/asListOfDocumentSymbols
class OutlineModel:	asListOfDocumentSymbols(): DocumentSymbol[] {
		const roots = this.getTopLevelSymbols();
		const bucket: DocumentSymbol[] = [];
		OutlineModel._flattenDocumentSymbols(bucket, roots, '');
		return bucket.sort((a, b) => Range.compareRangesUsingStarts(a.range, b.range));
	}