use_modular_headers (#42204)

diff --git a/examples/hello_world/ios/Runner/AppDelegate.m b/examples/hello_world/ios/Runner/AppDelegate.m
index b1a0c02..cafbf73 100644
--- a/examples/hello_world/ios/Runner/AppDelegate.m
+++ b/examples/hello_world/ios/Runner/AppDelegate.m
@@ -1,5 +1,5 @@
-#include "AppDelegate.h"
-#include "GeneratedPluginRegistrant.h"
+#import "AppDelegate.h"
+#import "GeneratedPluginRegistrant.h"
 
 @implementation AppDelegate
 
diff --git a/examples/hello_world/ios/Runner/GeneratedPluginRegistrant.h b/examples/hello_world/ios/Runner/GeneratedPluginRegistrant.h
index 3b700eb..ed9a5c6 100644
--- a/examples/hello_world/ios/Runner/GeneratedPluginRegistrant.h
+++ b/examples/hello_world/ios/Runner/GeneratedPluginRegistrant.h
@@ -7,8 +7,11 @@
 
 #import <Flutter/Flutter.h>
 
+NS_ASSUME_NONNULL_BEGIN
+
 @interface GeneratedPluginRegistrant : NSObject
 + (void)registerWithRegistry:(NSObject<FlutterPluginRegistry>*)registry;
 @end
 
+NS_ASSUME_NONNULL_END
 #endif /* GeneratedPluginRegistrant_h */