docs: cgroup-v1: make swap extension subsections subsections

Subsections text of swap extension section is marked up as bold text,
whereas making them proper subsection is more appropriate.

Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Bagas Sanjaya 2023-01-05 20:16:32 +07:00 • committed by Tejun Heo
commit 5fa16afc4b