Fix: Make the outline follow the page scroll

This can be considered a user experience issue. 

When the page is exceptionally long with numerous anchor points, the height of the right outline may exceed the screen height, causing the activated anchor points to become invisible.

 This issue is evident on this page https://vitepress.dev/reference/site-config. 

After adjustments, the activated anchor within the outline will scroll along with the page, without affecting the separate scrolling of the outline

src/client/theme-default/composables/outline.ts

@@ -183,6 +183,10 @@ export function useActiveAnchor(
       activeLink.classList.add('active')
       marker.value.style.top = activeLink.offsetTop + 33 + 'px'
       marker.value.style.opacity = '1'
+      activeLink.scrollIntoView({
+        behavior: 'smooth',
+        block: 'center'
+      })
     } else {
       marker.value.style.top = '33px'
       marker.value.style.opacity = '0'