fix(docs): add missing callout to database connection example

Author: razvan

docs/modules/hive/pages/usage-guide/database-driver.adoc

@@ -149,7 +149,7 @@ spec:
   image:
     productVersion: 4.2.0
   clusterConfig:
-    metadataDatabase:
+    metadataDatabase: # <1>
       mysql:
         host: mysql
         database: hive