docs: netdev: improve wording of reviewer guidance
Reword the reviewer guidance based on behavior we see on the list.
Steer folks:
- towards sending tags
- away from process issues.
Reviewed-by: Joe Damato <joe@dama.to>
Reviewed-by: Nicolai Buchwitz <nb@tipi-net.de>
Link: https://patch.msgid.link/20260406175334.3153451-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>