* Add containerd snapshotter flag
Signed-off-by: Jason-ZW <zhenyang@rancher.com>

* Fix CamelCase nit and option description
Signed-off-by: Brad Davidson <brad.davidson@rancher.com>
Signed-off-by: Jason-ZW <zhenyang@rancher.com>
Co-authored-by: Brad Davidson <brad@oatmail.org>