Mention versions require allow_experimental_(kusto|prql)_dialect

Author: rschu1ze

docs/en/guides/developer/alternative-query-languages.md

@@ -30,7 +30,7 @@ SET dialect = 'clickhouse'
 To enable PRQL:
 
 ```sql
-SET allow_experimental_prql_dialect = 1;
+SET allow_experimental_prql_dialect = 1; -- this SET statement is required only for ClickHouse versions >= v25.1
 SET dialect = 'prql'
 ```
 
@@ -54,7 +54,7 @@ Under the hood, ClickHouse uses transpilation from PRQL to SQL to run PRQL queri
 To enable KQL:
 
 ```sql
-SET allow_experimental_kusto_dialect = 1;
+SET allow_experimental_kusto_dialect = 1; -- this SET statement is required only for ClickHouse versions >= 25.1
 SET dialect = 'kusto'
 ```