update readme

Author: gh-yzou

plugins/spark/README.md

@@ -83,13 +83,13 @@ bin/spark-shell \
 ```
 
 # Limitations
-The Polaris Spark client supports catalog management for both Iceberg and None-Iceberg tables, it routes all Iceberg
-table requests to the Iceberg REST endpoints, and routes none-iceberg table requests to the Generic Table REST endpoints.
+The Polaris Spark client supports catalog management for both Iceberg and Delta tables, it routes all Iceberg table 
+requests to the Iceberg REST endpoints, and routes all Delta table requests to the Generic Table REST endpoints.
 
 Following describes the current limitations of the Polaris Spark client:
 1) Create table as select (CTAS) is not supported for Delta tables. As a result, the `saveAsTable` method of `Dataframe`
    is also not supported, since it relies on the CTAS support.
-2) Create a non-iceberg table without explicit location is not supported.
-3) Rename a table for non-iceberg table is not supported.
+2) Create a Delta table without explicit location is not supported.
+3) Rename a Delta table is not supported.
 4) ALTER TABLE ... SET LOCATION/SET FILEFORMAT/ADD PARTITION is not supported for DELTA table.
-5) No guarantee is provided for table types that are neither ICEBERG or DELTA at this moment, like csv.
+5) For other non-iceberg tables like csv, there is no specific guarantee provided today.