We've encountered a problem parsing statements like SELECT 1, sort FROM tbl which are valid in Snowflake.

The reason is that in the Snowflake dialect, supports_projection_trailing_commas is true. The flow then checks the keyword after the comma to see if it's reserved (FROM for example), and if not, it stops parsing the projection. However, the check relies on Dialect::is_column_alias which wasn't implemented in the Snowflake dialog.

The solution is to align the behavior of the Snowflake dialect to other dialects by overriding Dialect::is_column_alias instead of Dialect::is_select_item_alias.