extensions/typescript-language-features/src/languageFeatures/folding.ts/TypeScriptFoldingProvider/getFoldingRangeKind
class TypeScriptFoldingProvider:	private static getFoldingRangeKind(span: Proto.OutliningSpan): vscode.FoldingRangeKind | undefined {
		switch (span.kind) {
			case 'comment': return vscode.FoldingRangeKind.Comment;
			case 'region': return vscode.FoldingRangeKind.Region;
			case 'imports': return vscode.FoldingRangeKind.Imports;
			case 'code':
			default: return undefined;
		}
	}