pg_upgrade: Clarify one message

Reported-by: Dennis Björklund <db@zigo.dhs.org>

src/bin/pg_upgrade/check.c

@@ -894,7 +894,7 @@ check_for_reg_data_type_usage(ClusterInfo *cluster)
 	bool		found = false;
 	char		output_path[MAXPGPATH];
 
-	prep_status("Checking for reg* system OID user data types");
+	prep_status("Checking for reg* data types in user tables");
 
 	snprintf(output_path, sizeof(output_path), "tables_using_reg.txt");