Update xrefs (#624)

Author: Techassi

docs/modules/kafka/pages/usage.adoc

@@ -33,7 +33,7 @@ spec:
       default:
         replicas: 1
 ----
-If you wish to include integration with xref:opa::index.adoc[Open Policy Agent] and already have an OPA cluster, then you can include an `opa` field pointing to the OPA cluster discovery `ConfigMap` and the required package. The package is optional and will default to the `metadata.name` field:
+If you wish to include integration with xref:opa:index.adoc[Open Policy Agent] and already have an OPA cluster, then you can include an `opa` field pointing to the OPA cluster discovery `ConfigMap` and the required package. The package is optional and will default to the `metadata.name` field:
 
 [source,yaml]
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@@ -132,7 +132,7 @@ spec:
 
 == Encryption
 
-The internal and client communication can be encrypted TLS. This requires the xref:secret-operator::index.adoc[Secret Operator] to be present in order to provide certificates. The utilized certificates can be changed in a top-level config.
+The internal and client communication can be encrypted TLS. This requires the xref:secret-operator:index.adoc[Secret Operator] to be present in order to provide certificates. The utilized certificates can be changed in a top-level config.
 
 [source,yaml]
 ----
@@ -158,7 +158,7 @@ spec:
 <1> The `spec.clusterConfig.tls.serverSecretClass` refers to the client-to-server encryption. Defaults to the `tls` secret. Can be deactivated by setting `serverSecretClass` to `null`.
 <2> The `spec.clusterConfig.tls.internalSecretClass` refers to the broker-to-broker internal encryption. This must be explicitly set or defaults to `tls`. May be disabled by setting `internalSecretClass` to `null`.
 
-The `tls` secret is deployed from the xref:secret-operator::index.adoc[Secret Operator] and looks like this:
+The `tls` secret is deployed from the xref:secret-operator:index.adoc[Secret Operator] and looks like this:
 
 [source,yaml]
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@@ -181,7 +181,7 @@ You can create your own secrets and reference them e.g. in the `spec.clusterConf
 
 == Authentication
 
-The internal or broker-to-broker communication is authenticated via TLS. In order to enforce TLS authentication for client-to-server communication, you can set an `AuthenticationClass` reference in the custom resource provided by the xref:commons-operator::index.adoc[Commons Operator].
+The internal or broker-to-broker communication is authenticated via TLS. In order to enforce TLS authentication for client-to-server communication, you can set an `AuthenticationClass` reference in the custom resource provided by the xref:commons-operator:index.adoc[Commons Operator].
 
 [source,yaml]
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