added comment re. static mapping

Author: adwk67

test/stack/10-hdfs.yaml

@@ -43,6 +43,9 @@ spec:
           core-site.xml:
             hadoop.security.group.mapping: "tech.stackable.hadoop.StackableGroupMapper"
             hadoop.security.group.mapping.opa.url: "http://test-opa.default.svc.cluster.local:8081/v1/data/hdfs"
+            # The operator adds a default static mapping when kerberos is activated, see:
+            # https://github.com/stackabletech/hdfs-operator/blob/main/rust/operator-binary/src/kerberos.rs#L97-L101
+            # This should be removed so that the mapping implementation can provide this information instead:
             hadoop.user.group.static.mapping.overrides: ""
         replicas: 2
   dataNodes: