docs/zh_CN: Cleanup index.rst

Many */index in the Chinese index.rst are not in the same order as the
English version. Put them to where they should be.

Signed-off-by: Tang Yizhou <tangyizhou@huawei.com>
Reviewed-by: Yanteng Si <siyanteng@loongson.cn>
Link: https://lore.kernel.org/r/20211229024212.32752-2-tangyizhou@huawei.com


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