landlock: Minor reword of docs for TCP access rights

landlock: Minor reword of docs for TCP access rights

- Move ABI requirement next to each access right to prepare adding more
  access rights;
- Mention the possibility to remove the random component of a socket's
  ephemeral port choice within the netns-wide ephemeral port range,
  since it allows choosing the "random" ephemeral port.

Signed-off-by: Matthieu Buffet <matthieu@buffet.re>
Link: https://lore.kernel.org/r/20251212163704.142301-2-matthieu@buffet.re
Signed-off-by: Mickaël Salaün <mic@digikod.net>