docs(opensearch): remove duplicate words (#32593)

I deleted the duplicate `into 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)

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

Author: mazyu36

packages/aws-cdk-lib/aws-opensearchservice/lib/domain.ts

@@ -2120,7 +2120,7 @@ function extractNameFromEndpoint(domainEndpoint: string) {
 }
 
 /**
- * Converts an engine version into a into a decimal number with major and minor version i.e x.y.
+ * Converts an engine version into a decimal number with major and minor version i.e x.y.
  *
  * @param version The engine version object
  */