Update drawer.md

It sounds like you've identified an important point to add to the documentation about the vaul-drawer-wrapper attribute being necessary for the zoom effect in the Drawer component's background. Clarifying this in the documentation would be helpful for users encountering the same issue.

apps/www/src/content/docs/components/drawer.md

@@ -53,6 +53,11 @@ import {
   </Drawer>
 </template>
 ```
+### Scale Background
+If you want the background to have a zoom effect, you need to add the `vaul-drawer-wrapper` attribute to the root component.
+```html
+<div vaul-drawer-wrapper id="app"></div>
+```
 
 ## Examples