chore(s3): fix indent in sample code (#20457)

I found wrong indents in sample code and fix those.

----

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packages/@aws-cdk/aws-s3/README.md

@@ -522,15 +522,15 @@ by deploying with CDK version `1.126.0` or later **before** switching this value
 
 ```ts
 const bucket = new s3.Bucket(this, 'MyBucket', {
-   transferAcceleration: true,
+  transferAcceleration: true,
 });
 ```
 
 To access the bucket that is enabled for Transfer Acceleration, you must use a special endpoint. The URL can be generated using method `transferAccelerationUrlForObject`:
 
 ```ts
 const bucket = new s3.Bucket(this, 'MyBucket', {
-   transferAcceleration: true,
+  transferAcceleration: true,
 });
 bucket.transferAccelerationUrlForObject('objectname');
 ```
@@ -540,14 +540,14 @@ bucket.transferAccelerationUrlForObject('objectname');
 [Intelligent Tiering](https://docs.aws.amazon.com/AmazonS3/latest/userguide/intelligent-tiering.html) can be configured to automatically move files to glacier:
 
 ```ts
-    new s3.Bucket(this, 'MyBucket', {
-   intelligentTieringConfigurations: [{
-      name: 'foo',
-      prefix: 'folder/name',
-      archiveAccessTierTime: cdk.Duration.days(90),
-      deepArchiveAccessTierTime: cdk.Duration.days(180),
-      tags: [{key: 'tagname', value: 'tagvalue'}]
-   }],
+new s3.Bucket(this, 'MyBucket', {
+  intelligentTieringConfigurations: [{
+    name: 'foo',
+    prefix: 'folder/name',
+    archiveAccessTierTime: cdk.Duration.days(90),
+    deepArchiveAccessTierTime: cdk.Duration.days(180),
+    tags: [{key: 'tagname', value: 'tagvalue'}]
+  }],
 });
 
 ```