r/aws_sfn_activity(doc): document read-only arn attribute

Author: jar-b

.changelog/44408.txt

@@ -2,5 +2,8 @@
 resource/aws_sfn_activity: Add resource identity support
 ```
 ```release-note:enhancement
+resource/aws_sfn_activity: Add `arn` argument
+```
+```release-note:enhancement
 resource/aws_sfn_alias: Add resource identity support
 ```

website/docs/r/sfn_activity.html.markdown

@@ -55,9 +55,10 @@ This resource supports the following arguments:
 
 This resource exports the following attributes in addition to the arguments above:
 
-* `id` - The Amazon Resource Name (ARN) that identifies the created activity.
-* `name` - The name of the activity.
-* `creation_date` - The date the activity was created.
+* `id` - Amazon Resource Name (ARN) of the activity.
+* `arn` - Amazon Resource Name (ARN) of the activity.
+* `name` - Name of the activity.
+* `creation_date` - Date the activity was created.
 * `tags_all` - A map of tags assigned to the resource, including those inherited from the provider [`default_tags` configuration block](https://registry.terraform.io/providers/hashicorp/aws/latest/docs#default_tags-configuration-block).
 
 ## Import
@@ -81,13 +82,13 @@ In Terraform v1.5.0 and later, use an [`import` block](https://developer.hashico
 
 ```terraform
 import {
-  to = aws_sfn_activity.foo
+  to = aws_sfn_activity.example
   id = "arn:aws:states:eu-west-1:123456789098:activity:bar"
 }
 ```
 
 Using `terraform import`, import activities using the `arn`. For example:
 
 ```console
-% terraform import aws_sfn_activity.foo arn:aws:states:eu-west-1:123456789098:activity:bar
+% terraform import aws_sfn_activity.example arn:aws:states:eu-west-1:123456789098:activity:bar
 ```