KVM: Documentation: Minor fixups

In preparation for documenting a new capability let's fix up the
formatting of the current ones.

Signed-off-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Steven Price <steven.price@arm.com>
Link: https://lore.kernel.org/r/20200804170604.42662-6-drjones@redhat.com