Missing support for composite slots in AWS::Lex::SlotType

### Name of the resource

Other

### Resource name

AWS::Lex::SlotType

### Description

Hi there,
On the 9th of September Amazon announced a new feature in Amazon lex which is [composite slot type](https://aws.amazon.com/about-aws/whats-new/2022/09/amazon-lex-composite-slot-type/?nc1=h_ls).

I wanted to check if this feature is going to be implemented by cloud formation in the next period since I wanted to create a bot with a few composite slots based on the cdk but I noticed that the cdk provides only L1 support for lex which means that they support only what CloudFormation supports ([based on their answer](https://github.com/aws/aws-cdk/issues/22250) ).

### Other Details

_No response_

Start with the AWS::Lex::SlotType resource named in the issue and read the linked Amazon announcement for the composite slot type feature. Confirm the CloudFormation coverage needed for composite slots and consider the work complete when that resource supports the announced capability.

Written by the indexing model from the issue text.