l10n: Update zh_CN translation for 1.7.9.2

l10n: Update zh_CN translation for 1.7.9.2

In order to show detailed dirty status of submodules in long format,
git stripped the last ", " from the concatenate sting by a two-byte
backstep. So for keeping the two-byte backstep valid, won't touch the
end ", " for translation.

Signed-off-by: Jiang Xin <worldhello.net@gmail.com>