Feature request: Support for delimiter

Hi, thank you for creating such a great library.
It would be great if there is an option that we can specify the delimiter so that the formatter can ignore formatting it.
With current formatter, with the following sql text

DELIMITER //

CREATE FUNCTION FortyTwo() RETURNS TINYINT DETERMINISTIC
BEGIN
  DECLARE x TINYINT;
  SET x = 42;
  RETURN x;
END 
//

DELIMITER ; 

It returns this

DELIMITER / /
CREATE
   FUNCTION FortyTwo() RETURNS TINYINT DETERMINISTIC
BEGIN
   DECLARE x TINYINT;

SET x = 42;

RETURN x;

END / / DELIMITER;

Start from the formatter entry point and review how the current formatting behavior handles DELIMITER directives and the routine example shown in the issue. Define the expected preserved delimiter syntax and verify the example input produces the intended output; the payload names no specific file or test.