Show diagonal pattern on the card background-pattern docs example (#3039)

Closes #3032

.changeset/fix-background-pattern-docs-example.md

@@ -0,0 +1,5 @@
+---
+"@tabler/docs": patch
+---
+
+Fixed the "Card on a background pattern" docs example so the preview shows the `.bg-pattern-diagonal` background.

docs/content/ui/utilities/background-patterns.mdx

@@ -162,13 +162,13 @@ Use opacity utilities to control how strong the texture is:
 
 Look at the following examples to see how background patterns can be used in real layouts.
 
-### Card with background pattern
+### Card on a background pattern
 
-Card with a background pattern in the body can be used to add a decorative touch to the card. This is useful when you want to add a subtle pattern to the card without affecting the readability of the content.
+Placing a card on a patterned background adds a decorative touch to the surrounding area while keeping the card itself clean. Wrap the card in an element with a `.bg-pattern-*` class so the pattern shows around the card without affecting the readability of its content.
 
-<Example hideCode>
+<Example hideCode class="bg-pattern-diagonal">
   <div class="card">
-  <div class="card-body">Here is example of a card with a background pattern.</div>
+    <div class="card-body">Here is an example of a card placed on a background pattern.</div>
   </div>
 </Example>
 <Example codeOnly>