Update terminology for customer managed keys (#1616)

Author: hebelsan

docs/usage/usage.md

@@ -523,9 +523,9 @@ spec:
 ```
 
 > [!NOTE]
-> The AWS extension does not support EBS volume (root & data volumes) encryption with [customer managed CMK](https://docs.aws.amazon.com/kms/latest/developerguide/concepts.html#customer-cmk).
-> Support for [customer managed CMK](https://docs.aws.amazon.com/kms/latest/developerguide/concepts.html#customer-cmk) is out of scope for now.
-> Only [AWS managed CMK](https://docs.aws.amazon.com/kms/latest/developerguide/concepts.html#aws-managed-cmk) is supported.
+> The AWS extension does not support EBS volume (root & data volumes) encryption with [customer managed keys](https://docs.aws.amazon.com/kms/latest/developerguide/concepts.html#customer-mgn-key).
+> Support for [customer managed keys](https://docs.aws.amazon.com/kms/latest/developerguide/concepts.html#customer-mgn-key) is out of scope for now.
+> Only [AWS managed keys](https://docs.aws.amazon.com/kms/latest/developerguide/concepts.html#aws-managed-key) is supported.
 
 Additionally, it is possible to provide further AWS-specific values for configuring the worker pools. The additional configuration must be specified in the `providerConfig` field of the respective worker.
 ```yaml