[docs] add missing semicolon (#3305)

Add missing semicolon to code example

Author: Salakar

GoogleUtilities/AppDelegateSwizzler/README.md

@@ -169,7 +169,7 @@ by `[GULAppDelegateSwizzler proxyOriginalDelegate]`:
 
 - (void)application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo;
 
-- (void)application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo fetchCompletionHandler:(void (^)(UIBackgroundFetchResult result))completionHandler
+- (void)application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo fetchCompletionHandler:(void (^)(UIBackgroundFetchResult result))completionHandler;
 ```
 
 If you need to swizzle these methods you can call