l10n: zh_CN.po: translate 54 messages (2048t0f0u)

Translate 54 new messages came from git.pot update in c138af5
(l10n: git.pot: v1.8.3 round 1 (54 new, 15 removed))

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