Fixed example output for list-buckets --details

README.md

@@ -241,6 +241,7 @@ Add `--details` to include details of the bucket ACL, website configuration and
 Using `--details` adds three additional API calls for each bucket, so it is advisable to use it with one or more explicit bucket names.
 ```
 % s3-credentials list-buckets simonw-test-public-website-bucket --details
+[
   {
     "Name": "simonw-test-public-website-bucket",
     "CreationDate": "2021-11-08 22:53:30+00:00",
@@ -270,6 +271,7 @@ Using `--details` adds three additional API calls for each bucket, so it is advi
       }
     }
   }
+]
 ```
 A bucket with `public_access_block` might look like this:
 ```json