i18n: use zh-TW and zh-CN over zh-Hant and zh-Hans (#377)

Both crowdin and docsearch i18n configs use TW and CN over Hant and Hans. This should reduce some config confusions.
cc @ericnakagawa. Also, apparently you're working on algolia search i18n?

examples/translations/crowdin.yaml

@@ -41,8 +41,8 @@ files:
         'tr': 'tr'
         'uk': 'uk'
         'vi': 'vi'
-        'zh-CN': 'zh-Hans'
-        'zh-TW': 'zh-Hant'
+        'zh-CN': 'zh-CN'
+        'zh-TW': 'zh-TW'
   -
     source: '/website/i18n/en.json'
     translation: '/website/i18n/%locale%.json'

examples/translations/languages.js

@@ -174,8 +174,8 @@ const languages = [
   {
     enabled: false,
     name: '中文',
-    tag: 'zh-Hans',
+    tag: 'zh-CN',
   },
-  {enabled: false, name: '繁體中文', tag: 'zh-Hant'},
+  {enabled: false, name: '繁體中文', tag: 'zh-TW'},
 ];
 module.exports = languages;