feat(theme): make "Take me home" button's link customizable (vuejs#4658)

Author: zhangyx1998

src/client/theme-default/NotFound.vue

@@ -22,7 +22,7 @@ const { currentLang } = useLangs()
     <div class="action">
       <a
         class="link"
-        :href="withBase(currentLang.link)"
+        :href="withBase(theme.notFound?.link ?? currentLang.link)"
         :aria-label="theme.notFound?.linkLabel ?? 'go to home'"
       >
         {{ theme.notFound?.linkText ?? 'Take me home' }}

types/default-theme.d.ts

@@ -480,6 +480,13 @@ export namespace DefaultTheme {
      */
     quote?: string
 
+    /**
+     * Target of the home link.
+     *
+     * @default '/'
+     */
+    link?: string
+
     /**
      * Set aria label for home link.
      *