use more appropriate labels for chinese UI option

config/locales/names.yml

@@ -553,10 +553,10 @@ za:
   nativeName: Saɯ cueŋƅ
 zh:
   name: Chinese
-  nativeName: 中文
+  nativeName: 简体中文
 zh_TW:
   name: Chinese
-  nativeName: 中文 (TW)
+  nativeName: 繁體中文
 zu:
   name: Zulu
   nativeName: isiZulu

spec/models/locale_site_setting_spec.rb

@@ -30,8 +30,8 @@ describe LocaleSiteSetting do
 
     it 'returns native names' do
       expect(native_locale_name('de')).to eq('Deutsch')
-      expect(native_locale_name('zh_CN')).to eq('中文')
-      expect(native_locale_name('zh_TW')).to eq('中文 (TW)')
+      expect(native_locale_name('zh_CN')).to eq('简体中文')
+      expect(native_locale_name('zh_TW')).to eq('繁體中文')
     end
   end