Function lex_comment 

fn lex_comment(stream: &mut LocatingSlice<&'_ str>) -> Token

Process Comment

;; Comment

comment-start-symbol = %x23 ; #
non-ascii = %x80-D7FF / %xE000-10FFFF
non-eol = %x09 / %x20-7F / non-ascii

comment = comment-start-symbol *non-eol

Safety

• stream must be UTF-8
• stream[0] == b'#'