Update README.md

Author: haydenbaker

README.md

@@ -24,7 +24,7 @@ implementing MCP servers to interact with AWS services.
 
 The AWS models repository contains:
 
-* One top-level directory per service
+* Under `models/`, there is one directory per service
     * Top-level service directories are named using the `<sdk-id>` of the service, where `<sdk-id>` is the value of the
     model's [`sdkId`](https://smithy.io/2.0/aws/aws-core.html#sdkid), lowercased and with spaces converted to hyphens
 * Each service directory contains one directory per `<version>` of the service, where `<version>` is the value of the