pkg/shelf: formatted code

lib/src/response.dart

Index: lib/src/response.dart
diff --git a/lib/src/response.dart b/lib/src/response.dart
index f95fdb77ff6839ad43e825d9bb7188dc8c0bdc9a..029881305ae8f055908558087e87fb041eb5d791 100644
--- a/lib/src/response.dart
+++ b/lib/src/response.dart
@@ -276,8 +276,8 @@ Map<String, String> _adjustHeaders(
 /// Adds a header with [name] and [value] to [headers], which may be null.
 ///
 /// Returns a new map without modifying [headers].
-Map<String, String> _addHeader(Map<String, String> headers, String name,
-    String value) {
+Map<String, String> _addHeader(
+    Map<String, String> headers, String name, String value) {
   headers = headers == null ? {} : new Map.from(headers);
   headers[name] = value;
   return headers;