Clarify that the supplied RDAP Base URLs might get overridden

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=252661230

java/google/registry/tools/CreateOrUpdateRegistrarCommand.java

@@ -256,7 +256,10 @@ abstract class CreateOrUpdateRegistrarCommand extends MutatingCommand {
 
   @Parameter(
       names = "--rdap_servers",
-      description = "Comma-delimited list of RDAP servers. An empty argument clears the list")
+      description =
+          "Comma-delimited list of RDAP servers. An empty argument clears the list."
+              + " Note that for real registrars this could get overridden periodically by"
+              + " ICANN-registered values.")
   List<String> rdapServers = new ArrayList<>();
 
   /** Returns the existing registrar (for update) or null (for creates). */