translate datetime.rst:872 (#540)

* translate datetime.rst:872

* Update library/datetime.po

---------

Co-authored-by: Wei-Hsiang (Matt) Wang <mattwang44@gmail.com>

Author: pinerchen

library/datetime.po

@@ -1134,6 +1134,9 @@ msgid ""
 "going through a :func:`time.time` timestamp (for example, this may be "
 "possible on platforms supplying the C :c:func:`gettimeofday` function)."
 msgstr ""
+"如果選用的引數 *tz* 為 ``None`` 或未指定，則會像是 :meth:`today`，但盡可能提"
+"供比透過 :func:`time.time` 取得的時間戳記更多位數的資訊（例如，這在有提供 C "
+":c:func:`gettimeofday` 函式的平台上可能可行）。"
 
 #: ../../library/datetime.rst:878
 msgid ""