docs: make clear cache button adopt theming (#3010)

Author: Mnickii

stories/samples/general.stories.js

@@ -90,7 +90,7 @@ export const Localization = () => html`
 `;
 
 export const cache = () => html`
-<button id="ClearCacheButton" type="button">Clear Cache</button>
+<fluent-button id="ClearCacheButton" appearance="accent">Clear Cache</fluent-button>
 <div id="status" class="notes"></div>
 <span class="notes"
   >*Note* Please refer to your browser Developer Tools -> Applications -> Storage -> IndexedDB for cached