Update aws-resource-eventschemas-registrypolicy.md

[lumzs]

AWS::EventSchemas::RegistryPolicy Policy Statement Action prefixes should be schema not schemas. I tried to deploy a CloudFormation temple with a AWS::EventSchemas::RegistryPolicy similar to the examples in the documentation. Prefixing Policy Statement Actions with schemas yielded the following error:

Resource handler returned message: "Error occurred during operation 'CreateRegistryPolicy'." (RequestToken: <some-token>, HandlerErrorCode: GeneralServiceException)

I had to dig into the CloudTrail Event History to diagnose the problem.

Issue #, if available:

n/a

Description of changes:

Change examples of AWS::EventSchemas::RegistryPolicy Policy Statement Action prefixes from schema to schemas.

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.