report: add tooltip to qualify stackpack recommendations

report/renderer/category-renderer.js

@@ -92,6 +92,7 @@ export class CategoryRenderer {
         const snippets = this.dom.convertMarkdownLinkSnippets(pack.description);
         const packElm = this.dom.createElement('div', 'lh-audit__stackpack');
         packElm.append(packElmImg, snippets);
+        packElm.title = `Recommendation specific to ${pack.title} detected on the page`;
 
         this.dom.find('.lh-audit__stackpacks', auditEl)
           .append(packElm);