Fix typo: storter -> shorter

Author: delirious-lettuce

tests/test_buffer.py

@@ -71,7 +71,7 @@ def test_cursor_down(_buffer):
  _buffer.cursor_down()
  assert _buffer.document.cursor_position == len('line1\nlin')
 
- # Going down to a line that's storter.
+ # Going down to a line that's shorter.
  _buffer.reset()
  _buffer.insert_text('long line1\na\nb')
  _buffer.cursor_position = 3