doc/netlink: Add bitfield32, s8, s16 to the netlink-raw schema

The netlink-raw schema was not updated when bitfield32 was added
to the genetlink-legacy schema. It is needed for rtnetlink families.

s8 and s16 were also missing.

Signed-off-by: Donald Hunter <donald.hunter@gmail.com>
Link: https://lore.kernel.org/r/20231130214959.27377-2-donald.hunter@gmail.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>