doc: tutorial fix typo in cfg setting
doc: tutorial fix typo in cfg setting

Clarify the different methods of setting the configuration.

AlanJAS/pyusb,rabryan/pyusb,swinman/pyusb,rabryan/pyusb,h3nj3/pyusb,h3nj3/pyusb,swinman/pyusb,AlanJAS/pyusb