Better handling of IAM policy update (or any JSON)

Hi,

When updating an aws_iam_policy or aws_sqs_queue_policy, the changes in the Terraform plan are not displayed in a readable format. Instead, we only see a generic line like “big json” → “new big json,” which makes it difficult to review the actual modifications. Additionally, if the plan output is too large, it may appear truncated, further complicating the process (you have to download the full logs).