chore: simplify code

Author: brc-dd

src/client/theme-default/components/VPDocOutlineItem.vue

@@ -7,8 +7,8 @@ defineProps<{
 }>()
 
 function onClick({ target: el }: Event) {
-  const id = '#' + (el as HTMLAnchorElement).href!.split('#')[1]
-  const heading = document.getElementById(decodeURIComponent(id).slice(1))
+  const id = (el as HTMLAnchorElement).href!.split('#')[1]
+  const heading = document.getElementById(decodeURIComponent(id))
   heading?.focus()
 }
 </script>