aws-logs: Support for logs insights query folders missing from docs

### Describe the issue

When defining logs insight queries from the CloudWatch console, you have the ability to organize your queries into folders. The Logs Insights Query Definition construct also supports the ability to define folders when creating queries, by simply adding a / to the queryDefinitionName prop. This is a feature that many teams would find useful, and so it would be nice to update the docs to make it clear that this feature is also supported by the L2 construct, since there is currently no mention of it.

### Links

- https://docs.aws.amazon.com/cdk/api/v2/docs/aws-cdk-lib.aws_logs-readme.html
- https://docs.aws.amazon.com/cdk/api/v2/docs/aws-cdk-lib.aws_logs.QueryDefinition.html
- https://docs.aws.amazon.com/cdk/api/v2/docs/aws-cdk-lib.aws_logs.QueryDefinitionProps.html
- https://docs.aws.amazon.com/AmazonCloudWatch/latest/logs/CWL_Insights-Saving-Queries.html

Start with the aws-cdk-lib.aws_logs README and the QueryDefinition and QueryDefinitionProps API documentation linked in the issue. Confirm how queryDefinitionName supports slash-separated folders, then document that behavior and verify the resulting documentation clearly explains how to define a folder.

Written by the indexing model from the issue text.