Update quack hello_world to be hello world

Co-authored-by: Sam Ansmink <[email protected]>

extensions/quack/description.yml

@@ -14,6 +14,6 @@ repo:
 
 docs:
   hello_world: |
-    SELECT quack(i::VARCHAR) FROM range(10) tbl(i);
+    SELECT quack('world');
   extended_description: |
     The quack extension is based on DuckDB's [Extension Template](https://duckdb/extension_template/), and it's a great starting point to get started building more advanced extensions.