l10n: zh_CN.po: translate 76 new messages

Translate 76 new messages came from git.pot update in 3b6137f
(l10n: Update git.pot (76 new, 4 removed messages))

Thynson reviewed this update and also contributed other improvements:

 * blob -> 二进制对象（blob）
 * 共用 -> 同时使用

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

Author: jiangxin