[Resource Type] - [Enhancement] - Import AWS::DocDB::DBCluster resource

### Name of the resource

AWS::DocDB::DBCluster

### Resource name

_No response_

### Description

# Import AWS::DocDB::DBCluster resource type to CloudFormation stack

## Issue Description

I am attempting to import the `AWS::DocDB::DBCluster` resource type into a CloudFormation stack. However, when I execute the following AWS CLI command:

```
aws cloudformation create-change-set \
--stack-name docdb-import-stack \
--change-set-name import-docdb-change-set \
--change-set-type IMPORT \
--resources-to-import '[{"ResourceType":"AWS::DocDB::DBCluster","LogicalResourceId":"DocumentDBCluster","ResourceIdentifier":{"DBClusterIdentifier":"database-1"}}]' \
--template-body file://docdb-import.yml

I receive the following error message:

An error occurred (ValidationError) when calling the CreateChangeSet operation: ResourceTypes [AWS::DocDB::DBCluster] are not supported for Import

Verification
I have reviewed the [Resource type support documentation](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/resource-import-supported-resources.html?icmpid=docs_cfn_console) and confirmed that the AWS::DocDB::DBCluster resource type is not currently listed as supported for import.

Request
Could we please have the AWS::DocDB::DBCluster resource type added to the list of supported resources for import in CloudFormation?

Additional Information
AWS Service: CloudFormation
Resource Type: AWS::DocDB::DBCluster
Current Status: Not supported for import
Thank you for your attention to this matter.

### Other Details

_No response_

Start by reviewing the linked CloudFormation resource-import support documentation and reproducing the provided AWS CLI create-change-set command for AWS::DocDB::DBCluster. Done means the resource type is supported for CloudFormation IMPORT operations and the command no longer reports that it is unsupported.

Written by the indexing model from the issue text.