`BEGIN;` is formatted as `BEGIN TRANSACTION;`, which is invalid in MySQL

[lovasoa]

BEGIN; is valid in MySQL, but not BEGIN TRANSACTION;: https://dev.mysql.com/doc/refman/8.4/en/commit.html

But sqlparser does not preserve the exact syntax of the statement, and always formats it as BEGIN TRANSACTION;, causing an execution error in MySQL.

Found while investigating sqlpage/SQLPage#711