HADOOP-19278. review comment

Change-Id: I40445f2b5209dc1a8fc2aa3d695618fa4b6ecfe7

Author: steveloughran

hadoop-tools/hadoop-aws/src/site/markdown/tools/hadoop-aws/index.md

@@ -77,7 +77,7 @@ and compatible implementations.
 
 * Directly reads and writes S3 objects.
 * Compatible with standard S3 clients.
-* Compatible with files created by Amazon EMR's `s3://` client.
+* Compatible with files created by Amazon EMR's `s3://` client (EMRFS).
 * Supports partitioned uploads for many-GB objects.
 * Offers a high-performance random IO mode for working with columnar data such
 as Apache ORC and Apache Parquet files.