Correct Chinese quadrillion translations (#473)

Author: Plastic-time

src/humanize/locale/zh_CN/LC_MESSAGES/humanize.po

@@ -275,8 +275,8 @@ msgstr[1] "兆"
 #: src/humanize/number.py:212
 msgid "quadrillion"
 msgid_plural "quadrillion"
-msgstr[0] "万亿"
-msgstr[1] "万亿"
+msgstr[0] "千万亿"
+msgstr[1] "千万亿"
 
 #: src/humanize/number.py:213
 msgid "quintillion"

src/humanize/locale/zh_HK/LC_MESSAGES/humanize.po

@@ -276,8 +276,8 @@ msgstr[1] "兆"
 #: src/humanize/number.py:212
 msgid "quadrillion"
 msgid_plural "quadrillion"
-msgstr[0] "萬億"
-msgstr[1] "萬億"
+msgstr[0] "千萬億"
+msgstr[1] "千萬億"
 
 #: src/humanize/number.py:213
 msgid "quintillion"

tests/test_i18n.py

@@ -190,6 +190,19 @@ def test_naturaldelta() -> None:
 @pytest.mark.parametrize(
     "locale, number, expected_result",
     [
+        # Quadrillion is 10**15, or a thousand times a trillion.
+        ("zh_CN", 10**12, "1.0 兆"),
+        ("zh_CN", 10**15 - 1, "1.0 千万亿"),
+        ("zh_CN", 10**15, "1.0 千万亿"),
+        ("zh_CN", 2 * 10**15, "2.0 千万亿"),
+        ("zh_CN", -(10**15), "-1.0 千万亿"),
+        ("zh_CN", 10**18, "1.0 百京"),
+        ("zh_HK", 10**12, "1.0 兆"),
+        ("zh_HK", 10**15 - 1, "1.0 千萬億"),
+        ("zh_HK", 10**15, "1.0 千萬億"),
+        ("zh_HK", 2 * 10**15, "2.0 千萬億"),
+        ("zh_HK", -(10**15), "-1.0 千萬億"),
+        ("zh_HK", 10**18, "1.0 百京"),
         # Italian uses comma as decimal separator
         ("it_IT", 1_000_000, "1,0 milione"),
         ("it_IT", 1_200_000, "1,2 milioni"),