docs/scheduler/sched-design-CFS: formatting fix

Fix the rendering of the paragraph. Before the fix, the first line is
rendered in bold (I'm not quite sure why) and is also separated from the
rest of the paragraph, which is rendered with an indent.

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20210120001824.385168-3-kolyshkin@gmail.com


Signed-off-by: Jonathan Corbet <corbet@lwn.net>