[docs] Fix toolbar anatomy and styled component example closing tags (#4307)

Author: CiscoFran10

docs/src/app/(docs)/react/components/toolbar/page.mdx

@@ -30,7 +30,7 @@ import { Toolbar } from '@base-ui/react/toolbar';
   <Toolbar.Group>
     <Toolbar.Button />
     <Toolbar.Button />
-  <Toolbar.Group />
+  </Toolbar.Group>
   <Toolbar.Input />
 </Toolbar.Root>;
 ```

docs/src/app/(docs)/react/handbook/styling/page.mdx

@@ -149,9 +149,9 @@ const MenuExample = () => (
         <StyledMenuPopup>
           <StyledMenuItem>Add to Library</StyledMenuItem>
           <StyledMenuItem>Add to Playlist</StyledMenuItem>
-        </Menu.Portal>
+        </StyledMenuPopup>
       </StyledMenuPositioner>
-    </StyledMenuPopup>
+    </Menu.Portal>
   </Menu.Root>
 );