ClientConfigurer is only available in MaybeSecureClientConfigurationBuilder.

The documentation code does not compile and I'm not sure if it's a bug in the code or a miss in the documentation.

When you want to configure a client, the doc says to use:

```java
ClientConfiguration.builder().withClientConfigurer( // ...
```

But `withClientConfigurer(ClientConfiguration.ClientConfigurationCallback<?> clientConfigurer)` is only available in `TerminalClientConfigurationBuilder` interface.

And `ClientConfiguration.builder()` returns a `ClientConfigurationBuilderWithRequiredEndpoint` interface.

Author: dadoonet

src/main/antora/modules/ROOT/pages/elasticsearch/clients.adoc

@@ -192,6 +192,7 @@ This callback provides a `org.elasticsearch.client.RestClientBuilder` that can b
 [source,java]
 ----
 ClientConfiguration.builder()
+    .connectedTo("localhost:9200", "localhost:9291")
     .withClientConfigurer(ElasticsearchClients.ElasticsearchRestClientConfigurationCallback.from(restClientBuilder -> {
         // configure the Elasticsearch RestClient
         return restClientBuilder;
@@ -210,6 +211,7 @@ used by the `RestClient`.
 [source,java]
 ----
 ClientConfiguration.builder()
+    .connectedTo("localhost:9200", "localhost:9291")
     .withClientConfigurer(ElasticsearchClients.ElasticsearchHttpClientConfigurationCallback.from(httpAsyncClientBuilder -> {
         // configure the HttpAsyncClient
         return httpAsyncClientBuilder;