usage-guide: fix s2n_mode description (#2274)
usage-guide: fix s2n_mode description (#2274)


PKRoma/s2n,awslabs/s2n,awslabs/s2n,wcs1only/s2n,awslabs/s2n,wcs1only/s2n,wcs1only/s2n,PKRoma/s2n,PKRoma/s2n,wcs1only/s2n,PKRoma/s2n,wcs1only/s2n,PKRoma/s2n,PKRoma/s2n,awslabs/s2n,wcs1only/s2n,wcs1only/s2n,awslabs/s2n,PKRoma/s2n,awslabs/s2n,PKRoma/s2n,wcs1only/s2n