docs/zh_CN: add maintainer tree for Chinese doc pickup

From now on, the Chinese translation doc should be aimed here for base.

Signed-off-by: Alex Shi <alexs@kernel.org>
Cc: Yanteng Si <siyanteng@loongson.cn>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Yanteng Si <si.yanteng@linux.dev>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250213054222.21776-1-alexs@kernel.org