`aws_ses`: Email receiving section doesn't mention DNS entry for inbound-smtp.region.amazonaws.com

### Describe the issue

When the `aws_ses.EmailIdentity` construct is created, it handles creating the necessary DNS records for us, so the [Email sending documentation](https://docs.aws.amazon.com/cdk/api/v2/docs/aws-cdk-lib.aws_ses-readme.html#email-sending) doesn't have to mention DNS, but the `aws_ses.ReceiptRuleSet` construct does not handle any DNS records for us. Since the `ReceiptRuleSet` is unusable without the necessary DNS record, I think the CDK documentation should mention that some DNS records have to be created and maybe give a reference to the [Publishing an MX record for Amazon SES email receiving doc](https://docs.aws.amazon.com/ses/latest/dg/receiving-email-mx-record.html).

### Links

https://docs.aws.amazon.com/cdk/api/v2/docs/aws-cdk-lib.aws_ses-readme.html

Open the aws-cdk-lib.aws_ses README linked in the issue and locate the Email receiving or ReceiptRuleSet documentation. Read the linked Amazon SES MX-record guide for the required DNS context. Done means the CDK documentation explains that ReceiptRuleSet does not create the necessary DNS records and points readers to the receiving-email MX-record guide.

Written by the indexing model from the issue text.