src/vs/workbench/services/preferences/browser/preferencesService.ts/PreferencesService/openWorkspaceSettings
class PreferencesService:	openWorkspaceSettings(options: IOpenSettingsOptions = {}): Promise<IEditorPane | undefined> {
		if (!this.workspaceSettingsResource) {
			this.notificationService.info(nls.localize('openFolderFirst', "Open a folder or workspace first to create workspace or folder settings."));
			return Promise.reject(null);
		}

		options = {
			...options,
			target: ConfigurationTarget.WORKSPACE
		};
		return this.open(this.workspaceSettingsResource, options);
	}