docs/zh_CN: add a man-pages link to zh_CN/index.rst

update to commit 48987606 ("docs: add a man-pages link to the front
page")
Signed-off-by: Wu XiangCheng <bobwxc@email.cn>
Reviewed-by: Yanteng Si <siyanteng@loongson.cn>
Link: https://lore.kernel.org/r/6e289528ed1b40c1fcc03ea5e854e7c8ba264e67.1665467392.git.bobwxc@email.cnSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/translations/zh_CN/index.rst

@@ -97,6 +97,8 @@ TODOList:
 * 用户空间工具 <tools/index>
 * userspace-api/index
 
+也可参考独立于内核文档的 `Linux 手册页 <https://www.kernel.org/doc/man-pages/>`_ 。
+
 固件相关文档
 ------------