corrected typo in features.rst
corrected typo in features.rst

safwanrahman/readthedocs.org,rtfd/readthedocs.org,davidfischer/readthedocs.org,rtfd/readthedocs.org,safwanrahman/readthedocs.org,rtfd/readthedocs.org,davidfischer/readthedocs.org,safwanrahman/readthedocs.org,davidfischer/readthedocs.org,davidfischer/readthedocs.org,safwanrahman/readthedocs.org,rtfd/readthedocs.org