Docs: Small enhancements (#37803)

* Consistency with the doc

* Bring a class to avoid weird behavior

* Consistency + Add some explaining text

* fix(color)

site/content/docs/5.3/components/modal.md

@@ -488,7 +488,7 @@ exampleModal.addEventListener('show.bs.modal', event => {
   const button = event.relatedTarget
   // Extract info from data-bs-* attributes
   const recipient = button.getAttribute('data-bs-whatever')
-  // If necessary, you could initiate an AJAX request here
+  // If necessary, you could initiate an Ajax request here
   // and then do the updating in a callback.
   //
   // Update the modal's content.