docs/zh_CN: Update the translation of ksm to 6.1-rc8

Update to commit 21b7bdb5 ("ksm: add profit monitoring
documentation")

commit 94bfe85b ("mm/vmstat: add events for ksm cow")

Signed-off-by: Yanteng Si <siyanteng@loongson.cn>
Reviewed-by: Wu XiangCheng <bobwxc@email.cn>
Link: https://lore.kernel.org/r/4d11b3d7b7223c16b38ef913a6a6de108a0886d3.1670642548.git.siyanteng@loongson.cn


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