chore(bedrock): correct README now that L1 constructs are available (#29982)

### Reason for this change

Bedrock now supports CloudFormation resource types, and as of #29911 we now have L1 constructs for CDK.

### Description of changes

README previously stated that Bedrock was not available in CloudFormation.
I updated that to point people to Construct Hub and to the L1 constructs.

### Description of how you validated changes

N/A

### Checklist
- [x] My code adheres to the [CONTRIBUTING GUIDE](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md) and [DESIGN GUIDELINES](https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md)

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

Author: clareliguori

packages/aws-cdk-lib/aws-bedrock/README.md

@@ -3,8 +3,7 @@
 Amazon Bedrock is a fully managed service that offers a choice of foundation models (FMs)
 along with a broad set of capabilities for building generative AI applications.
 
-CloudFormation does not currently support any Bedrock resource types.
-This construct library is a collection of constructs that can look up existing Bedrock models
+This construct library provides a collection of constructs that can look up existing Bedrock models
 for use with other services' CDK constructs, such as AWS Step Functions.
 
 To look up a Bedrock base foundation model:
@@ -30,3 +29,8 @@ bedrock.ProvisionedModel.fromProvisionedModelArn(
   'arn:aws:bedrock:us-east-2:123456789012:provisioned-model/abc-123',
 );
 ```
+
+There are no official hand-written ([L2](https://docs.aws.amazon.com/cdk/latest/guide/constructs.html#constructs_lib)) constructs for provisioning Bedrock resources yet. Here are some suggestions on how to proceed:
+
+- Search [Construct Hub for Bedrock construct libraries](https://constructs.dev/search?q=bedrock)
+- Use the automatically generated [L1](https://docs.aws.amazon.com/cdk/latest/guide/constructs.html#constructs_l1_using) constructs, in the same way you would use [the CloudFormation AWS::Bedrock resources](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/AWS_Bedrock.html) directly.