Clarify what `elasticsearch_aws` actually is

app/views/admin/application_settings/_form.html.haml

@@ -461,14 +461,13 @@
           The url to use for connecting to Elasticsearch. Use a comma-separated list to support clustering (e.g., "http://localhost:9200, http://localhost:9201").
 
   %fieldset
-    %legend Elasticsearch AWS
+    %legend Elasticsearch AWS IAM credentials
     .form-group
       .col-sm-offset-2.col-sm-10
         .checkbox
           = f.label :elasticsearch_aws do
             = f.check_box :elasticsearch_aws
-            Using AWS hosted Elasticsearch
-
+            Using AWS hosted Elasticsearch with IAM credentials
     .form-group
       = f.label :elasticsearch_aws_region, 'AWS region', class: 'control-label col-sm-2'
       .col-sm-10

doc/integration/elasticsearch.md

@@ -57,10 +57,10 @@ The following Elasticsearch settings are available:
 | `Elasticsearch indexing`            | Enables/disables Elasticsearch indexing. You may want to enable indexing but disable search in order to give the index time to be fully completed, for example. Also keep in mind that this option doesn't have any impact on existing data, this only enables/disables background indexer which tracks data changes. So by enabling this you will not get your existing data indexed, use special rake task for that as explained in [Add GitLab's data to the Elasticsearch index](#add-gitlabs-data-to-the-elasticsearch-index). |
 | `Search with Elasticsearch enabled` | Enables/disables using Elasticsearch in search. |
 | `URL`                              | The URL to use for connecting to Elasticsearch. Use a comma-separated list to support clustering (e.g., "http://host1, https://host2:9200"). |
-| `AWS` | Sign your Elasticsearch requests using [AWS IAM authorization][aws-iam]. The access key must be allowed to perform `es:*` actions. |
-| `Region` | The AWS region your Elasticsearch service is located in. |
-| `Access Key` | The AWS access key. |
-| `Secret Access Key` | The AWS secret access key. |
+| `Using AWS hosted Elasticsearch with IAM credentials` | Sign your Elasticsearch requests using [AWS IAM authorization][aws-iam]. The access key must be allowed to perform `es:*` actions. |
+| `AWS Region` | The AWS region your Elasticsearch service is located in. |
+| `AWS Access Key` | The AWS access key. |
+| `AWS Secret Access Key` | The AWS secret access key. |
 
 ## Add GitLab's data to the Elasticsearch index