docs(kafka-connect): wrap cluster config in 'config' block

The example configuration nested 'clusters' directly under
'jikkou.provider.kafkaconnect', but the runtime only forwards
the nested 'config' block to a provider's configure(...) method.
Following the documented form caused the provider to resolve
an empty cluster list and fail with KafkaConnectClusterNotFoundException.

Aligns the example with every other provider doc (Kafka, Schema Registry,
Aiven, Confluent Cloud, Iceberg, AWS) and fixes a 'locahost' typo.

Closes #764

Author: fhussonnois

docs/content/en/docs/Providers/Kafka Connect/Configuration/_index.md

@@ -21,43 +21,45 @@ through the Jikkou client configuration property: `jikkou.provider.kafkaconnect`
 ```hocon
 jikkou {
   provider.kafkaconnect {
-    enabled: true
-    type: io.jikkou.kafka.connect.KafkaConnectExtensionProvider
-    # Array of Kafka Connect clusters configurations.
-    clusters = [
-      {
-        # Name of the cluster (e.g., dev, staging, production, etc.)
-        name = "locahost"
-        # URL of the Kafka Connect service
-        url = "http://localhost:8083"
-        # Method to use for authenticating on Kafka Connect. Available values are: [none, basicauth, ssl]
-        authMethod = none
-        # Use when 'authMethod' is 'basicauth' to specify the username for Authorization Basic header
-        basicAuthUser = null
-        # Use when 'authMethod' is 'basicauth' to specify the password for Authorization Basic header
-        basicAuthPassword = null
-        # Enable debug logging
-        debugLoggingEnabled = false
-  
-        # Ssl Config: Use when 'authMethod' is 'ssl'
-        # The location of the key store file.
-        sslKeyStoreLocation = "/certs/registry.keystore.jks"
-        # The file format of the key store file.
-        sslKeyStoreType = "JKS"
-        # The password for the key store file.
-        sslKeyStorePassword = "password"
-        # The password of the private key in the key store file.
-        sslKeyPassword = "password"
-        # The location of the trust store file.
-        sslTrustStoreLocation = "/certs/registry.truststore.jks"
-        # The file format of the trust store file.
-        sslTrustStoreType = "JKS"
-        # The password for the trust store file.
-        sslTrustStorePassword = "password"
-        # Specifies whether to ignore the hostname verification.
-        sslIgnoreHostnameVerification = true
-      }
-    ]
+    enabled = true
+    type = io.jikkou.kafka.connect.KafkaConnectExtensionProvider
+    config = {
+      # Array of Kafka Connect clusters configurations.
+      clusters = [
+        {
+          # Name of the cluster (e.g., dev, staging, production, etc.)
+          name = "localhost"
+          # URL of the Kafka Connect service
+          url = "http://localhost:8083"
+          # Method to use for authenticating on Kafka Connect. Available values are: [none, basicauth, ssl]
+          authMethod = none
+          # Use when 'authMethod' is 'basicauth' to specify the username for Authorization Basic header
+          basicAuthUser = null
+          # Use when 'authMethod' is 'basicauth' to specify the password for Authorization Basic header
+          basicAuthPassword = null
+          # Enable debug logging
+          debugLoggingEnabled = false
+
+          # Ssl Config: Use when 'authMethod' is 'ssl'
+          # The location of the key store file.
+          sslKeyStoreLocation = "/certs/registry.keystore.jks"
+          # The file format of the key store file.
+          sslKeyStoreType = "JKS"
+          # The password for the key store file.
+          sslKeyStorePassword = "password"
+          # The password of the private key in the key store file.
+          sslKeyPassword = "password"
+          # The location of the trust store file.
+          sslTrustStoreLocation = "/certs/registry.truststore.jks"
+          # The file format of the trust store file.
+          sslTrustStoreType = "JKS"
+          # The password for the trust store file.
+          sslTrustStorePassword = "password"
+          # Specifies whether to ignore the hostname verification.
+          sslIgnoreHostnameVerification = true
+        }
+      ]
+    }
   }
 }
 ```