docs: allow passing extra packages for ep-playground (element-plus#22979)

docs: allow passing extra packages

Author: Dsaquel

docs/.vitepress/vitepress/composables/use-playground.ts

@@ -18,23 +18,27 @@ export const usePlayground = (source: string) => {
 
   const encoded = code ? utoa(JSON.stringify(originCode)) : ''
 
-  let link = `https://element-plus.run/`
+  const link = new URL('https://element-plus.run/')
 
   if (usePreview()) {
-    link = `${link}?pr=${usePreviewPR()}`
+    link.searchParams.append('pr', usePreviewPR())
   }
 
   if (isDark.value) {
-    link = `${link}${usePreview() ? '&' : '?'}theme=dark`
+    link.searchParams.append('theme', 'dark')
+  }
+
+  if (code.includes('@vueuse/core')) {
+    link.searchParams.append('extra_packages', '@vueuse/core')
   }
 
   if (code) {
-    link += `#${encoded}`
+    link.hash = encoded
   }
 
   return {
     encoded,
-    link,
+    link: link.toString(),
   }
 }