docs: def text_coords(string, position):
      r"""
      Transform a simple index into a human-readable position in a string.
  
      This function accepts a string and an index, and will return a triple of
      `(lineno, columnno, line)` representing the position through the text. It's
      useful for displaying a string index in a human-readable way::
  
          >>> s = "abcdef\nghijkl\nmnopqr\nstuvwx\nyz"
          >>> text_coords(s, 0)
          (0, 0, 'abcdef')
          >>> text_coords(s, 4)
          (0, 4, 'abcdef')
          >>> text_coords(s, 6)
          (0, 6, 'abcdef')
          >>> text_coords(s, 7)
          (1, 0, 'ghijkl')
          >>> text_coords(s, 11)
          (1, 4, 'ghijkl')
          >>> text_coords(s, 15)
          (2, 1, 'mnopqr')
      """
      line_start = string.rfind('\n', 0, position) + 1
      line_end = string.find('\n', position)
      lineno = string.count('\n', 0, position)
      columnno = position - line_start
      line = string[line_start:line_end]
      return (lineno, columnno, line)