Update acknowledgements

README.rst

@@ -351,10 +351,10 @@ License
 python-chess is licensed under the GPL3. See the LICENSE file for the
 full copyright and license information.
 
-Thanks to Sam Tannous for publishing his approach to `avoid rotated bitboards
-with direct lookup (pdf) <http://arxiv.org/pdf/0704.3773.pdf>`_ alongside
-his GPL2+ engine `Shatranj <https://github.com/stannous/shatranj>`_. Some of
-the bitboard move generation parts are ported from there.
+Thanks to the Stockfish authors. Thanks to Sam Tannous for publishing his
+approach to `avoid rotated bitboards with direct lookup (pdf) <http://arxiv.org/pdf/0704.3773.pdf>`_
+alongside his GPL2+ engine `Shatranj <https://github.com/stannous/shatranj>`_.
+Some move generation ideas are taken from these sources.
 
 Thanks to Ronald de Man for his Syzygy endgame tablebases
 (https://github.com/syzygy1/tb). The probing code in