trivial: cgroups: documentation typo and spelling corrections

Minor typo and spelling corrections fixed whilst reading
to learn about cgroups capabilities.

Signed-off-by: Chris Samuel <chris@csamuel.org>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
4 files changed