Add prompt

Author: szarnyasg

_posts/2025-03-12-duckdb-ui.md

@@ -36,7 +36,7 @@ duckdb -ui
 
 You can also run the following SQL command from a [DuckDB client]({% link docs/stable/clients/overview.md %}) (e.g., CLI, Python, Java, etc.):
 
-```sql
+```plsql
 CALL start_ui();
 ```