Fix broken Markdown headings

Author: bryant1410

README.md

@@ -397,7 +397,7 @@ This sample demonstrates how to upload / download multiple files simultaneously
 * [Amazon S3](http://aws.amazon.com/s3/)
 * [Amazon Cognito Identity](http://aws.amazon.com/cognito/)
 
-###S 3 Transfer Utility Sample ([Swift](https://github.com/awslabs/aws-sdk-ios-samples/tree/master/S3BackgroundTransfer-Sample/Swift/), [Objective-C](https://github.com/awslabs/aws-sdk-ios-samples/tree/master/S3BackgroundTransfer-Sample/Objective-C/))
+### S 3 Transfer Utility Sample ([Swift](https://github.com/awslabs/aws-sdk-ios-samples/tree/master/S3BackgroundTransfer-Sample/Swift/), [Objective-C](https://github.com/awslabs/aws-sdk-ios-samples/tree/master/S3BackgroundTransfer-Sample/Objective-C/))
 
 This sample demonstrates how to use the Amazon S3 PreSigned URL Builder to download / upload files in background.