code: def find_next_character(code, position, char):
      
      end = LineCol(code, *position)
      while not end.eof and end.char() in WHITESPACE:
          end.inc()
  
      if not end.eof and end.char() == char:
          return end.tuple(), inc_tuple(end.tuple())
      return None, None
docs: Find next char and return its first and last positions