doc: Improve Japanese lxc-ps(1)

Signed-off-by: KATOH Yasufumi <karma@jazz.email.ne.jp>
doc: Improve Japanese lxc-restart(1)

Signed-off-by: KATOH Yasufumi <karma@jazz.email.ne.jp>
doc: Improve Japanese lxc-snapshot(1)

Signed-off-by: KATOH Yasufumi <karma@jazz.email.ne.jp>