[DOCS] Update client.asciidoc

Should be classpath rather than classloader.

Close #5965

docs/java-api/client.asciidoc

@@ -55,7 +55,7 @@ explicitly using the `clusterName` method on the builder.
 
 You can define `cluster.name` in `/src/main/resources/elasticsearch.yml`
 dir in your project. As long as `elasticsearch.yml` is present in the
-classloader, it will be used when you start your node.
+classpath, it will be used when you start your node.
 
 [source,java]
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