fix(docs): Update Back to top documentation to use jsx syntax (#3061)

Author: louismaximepiton

site/src/content/docs/components/back-to-top.mdx

@@ -35,7 +35,7 @@ Smooth scrolling does not depend on this component. It’s turned on only when t
   </nav>
 </div>
 
-<Example  showPreview="false" code={`<nav aria-label="Back to top" class="back-to-top">
+<Example showPreview={false} code={`<nav aria-label="Back to top" class="back-to-top">
     <a href="#top" class="back-to-top-link btn btn-icon btn-outline-secondary" data-bs-label="Back to top">
       <span class="visually-hidden">Back to top</span>
     </a>
@@ -52,7 +52,7 @@ You may use another `id`, but if you’re using a fixed header you’ll need to
 
 Add `.position-fixed` utility to your `.back-to-top-link` to make your back-to-top link persistent.
 
-<Example  showPreview="false" code={`<nav aria-label="Fixed back to top example" class="back-to-top">
+<Example showPreview={false} code={`<nav aria-label="Fixed back to top example" class="back-to-top">
     <a href="#top" class="back-to-top-link position-fixed btn btn-icon btn-outline-secondary" data-bs-label="Back to top">
       <span class="visually-hidden">Back to top</span>
     </a>
@@ -69,7 +69,7 @@ Use a `title` attribute instead of `data-bs-label` to ensure a visible label is
     </a>
   </nav>
 </div>
-<Example  showPreview="false" code={`<nav aria-label="Back to top" class="back-to-top">
+<Example showPreview={false} code={`<nav aria-label="Back to top" class="back-to-top">
     <a href="#top" class="back-to-top-link btn btn-icon btn-outline-secondary" title="Back to top">
       <span class="visually-hidden">Back to top</span>
     </a>