docs(spinners): improve buttons examples accessibility (twbs#38632)

* docs(spinners): improve buttons examples accessibility

* docs(spinners): missed occurrence of wrong role + aria-hidden

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Co-authored-by: Patrick H. Lauke <redux@splintered.co.uk>

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

@@ -96,8 +96,8 @@ Use [flexbox utilities][flex], [float utilities][float], or [text alignment][tex
 
 {{< example >}}
 <div class="d-flex align-items-center">
-  <strong>Loading...</strong>
-  <div class="spinner-border ms-auto" role="status" aria-hidden="true"></div>
+  <strong role="status">Loading...</strong>
+  <div class="spinner-border ms-auto" aria-hidden="true"></div>
 </div>
 {{< /example >}}
 
@@ -151,23 +151,23 @@ Use spinners within buttons to indicate an action is currently processing or tak
 
 {{< example >}}
 <button class="btn btn-primary" type="button" disabled>
-  <span class="spinner-border spinner-border-sm" role="status" aria-hidden="true"></span>
-  <span class="visually-hidden">Loading...</span>
+  <span class="spinner-border spinner-border-sm" aria-hidden="true"></span>
+  <span class="visually-hidden" role="status">Loading...</span>
 </button>
 <button class="btn btn-primary" type="button" disabled>
-  <span class="spinner-border spinner-border-sm" role="status" aria-hidden="true"></span>
-  Loading...
+  <span class="spinner-border spinner-border-sm" aria-hidden="true"></span>
+  <span role="status">Loading...</span>
 </button>
 {{< /example >}}
 
 {{< example >}}
 <button class="btn btn-primary" type="button" disabled>
-  <span class="spinner-grow spinner-grow-sm" role="status" aria-hidden="true"></span>
-  <span class="visually-hidden">Loading...</span>
+  <span class="spinner-grow spinner-grow-sm" aria-hidden="true"></span>
+  <span class="visually-hidden" role="status">Loading...</span>
 </button>
 <button class="btn btn-primary" type="button" disabled>
-  <span class="spinner-grow spinner-grow-sm" role="status" aria-hidden="true"></span>
-  Loading...
+  <span class="spinner-grow spinner-grow-sm" aria-hidden="true"></span>
+  <span role="status">Loading...</span>
 </button>
 {{< /example >}}