Format fix.

Author: westy92

lib/src/holiday_event_api.dart

@@ -9,7 +9,7 @@ import 'package:http/http.dart';
 /// The Official Holiday and Event API for Dart and Flutter.
 class HolidayEventApi {
   /// Creates a [HolidayEventApi] using the provided [apiKey].
-  /// 
+  ///
   /// Get one at https://apilayer.com/marketplace/checkiday-api#pricing.
   HolidayEventApi(String apiKey) {
     if (apiKey.isEmpty) {