Syntax:  SET LANGUAGE BRACKETED COMMENTS begin_string end_string
              add_remove defined_language

  Specifies the character sequences of comments in the language.

  This command defines the character sequences that start and end
  bracketed comments.  A bracketed comment begins and ends with
  explicit comment delimiters.  (Note that the beginning and ending
  comment delimiters can be the same but need not be.)

  Bracketed comments are recognized by the formatting commands (see the
  ALIGN and FILL commands) and placeholder operations (see the ERASE
  PLACEHOLDER command and the SET PLACEHOLDER DUPLICATION command).