fix(mixins-preview): service exports are different then in aws-cdk-lib (#36201)

### Issue

Fixes #36210

### Reason for this change

`@aws-cdk/mixins-preview` exports services as `aws_s3` (note the underscore).
But `aws-cdk-lib` exports them as `aws-s3` (note the dash).

The intention was to align how the exports are named for ease of future migration. Better to fix this now.

### Description of changes

Renaming `aws_<SERVICE>` to `aws-<service>` and the required update of `cdk-generate-synthetic-examples`.

### Describe any new or updated permissions being added

n/a

### Description of how you validated changes

test pipeline

### 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: mrgrain

package.json

@@ -23,7 +23,7 @@
     "@types/prettier": "2.6.0",
     "@yarnpkg/lockfile": "^1.1.0",
     "aws-sdk-js-codemod": "^2.4.5",
-    "cdk-generate-synthetic-examples": "^0.2.36",
+    "cdk-generate-synthetic-examples": "^0.2.37",
     "conventional-changelog-cli": "^2.2.2",
     "fs-extra": "^9.1.0",
     "graceful-fs": "^4.2.11",

packages/@aws-cdk/mixins-preview/README.md

@@ -140,7 +140,7 @@ Configures vended logs delivery for supported resources to various destinations:
 
 ```typescript
 import '@aws-cdk/mixins-preview/with';
-import * as cloudfrontMixins from '@aws-cdk/mixins-preview/aws_cloudfront/mixins';
+import * as cloudfrontMixins from '@aws-cdk/mixins-preview/aws-cloudfront/mixins';
 
 // Create CloudFront distribution
 declare const bucket: s3.Bucket;
@@ -197,9 +197,9 @@ Mixins.of(bucket).apply(new CfnBucketPropsMixin(
 Property mixins are available for all AWS services:
 
 ```typescript
-import { CfnLogGroupPropsMixin } from '@aws-cdk/mixins-preview/aws_logs/mixins';
-import { CfnFunctionPropsMixin } from '@aws-cdk/mixins-preview/aws_lambda/mixins';
-import { CfnTablePropsMixin } from '@aws-cdk/mixins-preview/aws_dynamodb/mixins';
+import { CfnLogGroupPropsMixin } from '@aws-cdk/mixins-preview/aws-logs/mixins';
+import { CfnFunctionPropsMixin } from '@aws-cdk/mixins-preview/aws-lambda/mixins';
+import { CfnTablePropsMixin } from '@aws-cdk/mixins-preview/aws-dynamodb/mixins';
 ```
 
 ### Error Handling
@@ -225,7 +225,7 @@ CDK Mixins automatically generates typed EventBridge event patterns for AWS reso
 ### Event Patterns Basic Usage
 
 ```typescript
-import { BucketEvents } from '@aws-cdk/mixins-preview/aws_s3/events';
+import { BucketEvents } from '@aws-cdk/mixins-preview/aws-s3/events';
 import * as events from 'aws-cdk-lib/aws-events';
 import * as targets from 'aws-cdk-lib/aws-events-targets';
 
@@ -259,7 +259,7 @@ new events.CfnRule(scope, 'CfnRule', {
 **Automatic Resource Injection**: Resource identifiers are automatically included in patterns
 
 ```typescript
-import { BucketEvents } from '@aws-cdk/mixins-preview/aws_s3/events';
+import { BucketEvents } from '@aws-cdk/mixins-preview/aws-s3/events';
 
 declare const bucket: s3.Bucket;
 const bucketEvents = BucketEvents.fromBucket(bucket);
@@ -272,7 +272,7 @@ const pattern = bucketEvents.objectCreatedPattern();
 **Event Metadata Support**: Control EventBridge pattern metadata
 
 ```typescript
-import { BucketEvents } from '@aws-cdk/mixins-preview/aws_s3/events';
+import { BucketEvents } from '@aws-cdk/mixins-preview/aws-s3/events';
 
 declare const bucket: s3.Bucket;
 const bucketEvents = BucketEvents.fromBucket(bucket);
@@ -299,5 +299,5 @@ Event patterns are generated for EventBridge events available in the AWS Event S
 Import events from service-specific modules:
 
 ```typescript
-import { BucketEvents } from '@aws-cdk/mixins-preview/aws_s3/events';
+import { BucketEvents } from '@aws-cdk/mixins-preview/aws-s3/events';
 ```