doc/general: update after e4e4add0e3ba7

Signed-off-by: Paul B Mahol <onemda@gmail.com>
swr: add native_simd_one

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
swr: Fix dithering of s16 with SIMD

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>