DATACASS-516 - Polishing.

Apply fix also to reactive Cassandra example.

Original pull request: #117.

src/main/asciidoc/reference/reactive-cassandra.adoc

@@ -233,7 +233,7 @@ public class AppConfig extends AbstractReactiveCassandraConfiguration {
   /*
    * Provide a keyspace name to the configuration.
    */
-  public getKeyspaceName() {
+  public String getKeyspaceName() {
     return "mykeyspace";
   }
 }