IGListBatchContext.h files need new header format

⚠️ OSS Workshop issue. Please do not action unless at my workshop.

IGListBatchContext.h files need new header format

```
//
// Copyright (c) 2016-present, Facebook, Inc.
// All rights reserved.
//
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same directory.
//
// GitHub:
// https://github.com/Instagram/IGListKit
//
// Documentation:
// https://instagram.github.io/IGListKit/
//
```

Open the IGListBatchContext.h file and compare its current header with the format shown in the issue. Done means the file uses the requested header format; no test is named in the issue.

Written by the indexing model from the issue text.