chore: correct comment syntax in PR template for IAM permissions (#32793)

The comment regarding IAM permissions was not properly commented out.
So I've fixed.

### 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

.github/PULL_REQUEST_TEMPLATE.md

@@ -16,7 +16,7 @@ What AWS use cases does this change enable? To enable the use cases, which AWS s
 
 ### Describe any new or updated permissions being added
 
-<!— What new or updated IAM permissions are needed to support the changes being introduced ? -->
+<!-- What new or updated IAM permissions are needed to support the changes being introduced ? -->
 
 
 ### Description of how you validated changes