net/nanocoap: Fix return value doc for coap_opt_add_uqueryX()
net/nanocoap: Fix return value doc for coap_opt_add_uqueryX()

OTAkeys/RIOT,yogo1212/RIOT,basilfx/RIOT,miri64/RIOT,ant9000/RIOT,authmillenon/RIOT,authmillenon/RIOT,OlegHahm/RIOT,basilfx/RIOT,jasonatran/RIOT,miri64/RIOT,RIOT-OS/RIOT,RIOT-OS/RIOT,yogo1212/RIOT,OlegHahm/RIOT,kaspar030/RIOT,kYc0o/RIOT,ant9000/RIOT,ant9000/RIOT,authmillenon/RIOT,basilfx/RIOT,yogo1212/RIOT,RIOT-OS/RIOT,jasonatran/RIOT,kYc0o/RIOT,kaspar030/RIOT,ant9000/RIOT,ant9000/RIOT,jasonatran/RIOT,authmillenon/RIOT,OlegHahm/RIOT,OTAkeys/RIOT,RIOT-OS/RIOT,kYc0o/RIOT,basilfx/RIOT,kaspar030/RIOT,OlegHahm/RIOT,miri64/RIOT,jasonatran/RIOT,OTAkeys/RIOT,yogo1212/RIOT,basilfx/RIOT,authmillenon/RIOT,kaspar030/RIOT,yogo1212/RIOT,OlegHahm/RIOT,kaspar030/RIOT,kYc0o/RIOT,authmillenon/RIOT,jasonatran/RIOT,miri64/RIOT,kYc0o/RIOT,RIOT-OS/RIOT,yogo1212/RIOT,OTAkeys/RIOT,miri64/RIOT,OTAkeys/RIOT