language selector always has english (#527)

* language selector always has english

If I don't understand chinese, how will I find the english translation
if the language selector is also chinese?

* add emoji, why not

docs/.vuepress/theme.ts

@@ -27,8 +27,8 @@ export default defaultTheme({
       danger: '警告',
       lastUpdatedText: '最近更改',
       selectLanguageName: '简体中文',
-      selectLanguageText: '多语言',
-      selectLanguageAriaLabel: '多语言',
+      selectLanguageText: '🌏 简体中文 / Change language',
+      selectLanguageAriaLabel: '简体中文 / Change language',
       docsDir: 'docs',
       backToHome: 'back to home',
       openInNewWindow: 'open in new tag',
@@ -40,8 +40,8 @@ export default defaultTheme({
       sidebar: sidebarEn,
       navbar: navbarEn,
       selectLanguageName: 'English (WIP)',
-      selectLanguageText: 'Multiple language',
-      selectLanguageAriaLabel: 'Multiple language',
+      selectLanguageText: '🌏 简体中文 / Change language',
+      selectLanguageAriaLabel: '简体中文 / Change language',
       editLinkText: 'Help us improve this page on GitHub！',
       lastUpdatedText: 'Last Updated',
       contributorsText: 'contributors',