Add @@SESSION as reserved word for MySQL

[zendesk-jjtheo]

@@SESSION is a reserved word in MySQL. https://dev.mysql.com/doc/refman/8.0/en/session-state-tracking.html
The formatter is currently adding a space after the first @ as it's considering it as a special word char.

Maybe a same fix as #42 would work? although it's not an operator in MySQL

[vertical-blank]

@zendesk-jjtheo
As a workaround, try this.

String sql = SqlFormatter.extend(cfg -> cfg.plusReservedWords("@@SESSION"))
            .format("SET @@SESSION.session_track_transaction_info='CHARACTERISTICS';");
System.out.println(sql);

output:

SET
  @@SESSION.session_track_transaction_info = 'CHARACTERISTICS';

[zendesk-jjtheo]

@vertical-blank Thank you!