note improvements to iprofile
note improvements to iprofile

The docs had fallen behind a bit ... iprofile is no longer usually necessary.

see https://github.com/libvips/libvips/issues/1843

lovell/libvips,lovell/libvips,lovell/libvips,jcupitt/libvips,lovell/libvips,jcupitt/libvips,jcupitt/libvips,jcupitt/libvips