src/vs/editor/contrib/folding/browser/folding.ts/UnfoldAllRegionsAction/invoke
class UnfoldAllRegionsAction:	invoke(_foldingController: FoldingController, foldingModel: FoldingModel, editor: ICodeEditor, args: void, languageConfigurationService: ILanguageConfigurationService): void {
		if (foldingModel.regions.hasTypes()) {
			setCollapseStateForType(foldingModel, FoldingRangeKind.Region.value, false);
		} else {
			const editorModel = editor.getModel();
			if (!editorModel) {
				return;
			}
			const foldingRules = languageConfigurationService.getLanguageConfiguration(editorModel.getLanguageId()).foldingRules;
			if (foldingRules && foldingRules.markers && foldingRules.markers.start) {
				const regExp = new RegExp(foldingRules.markers.start);
				setCollapseStateForMatchingLines(foldingModel, regExp, false);
			}
		}
	}