recommend failure aggregation

_includes/group_expectations.html

@@ -43,5 +43,7 @@ <h2 id="group-expectations">
 {% endhighlight %}
   </div>
 
+  <p>We recommend enabling <a href="https://rspec.toolboxforweb.xyz/docs/rspec-core/expectation_framework_integration/aggregating_failures#enable-failure-aggregation-globally-using-define_derived_metadata" target="_blank">failure aggregation globally</a> to make it list all failures at once.</p>
+
   <a class="discuss-link" target="_blank" href="https://github.com/evenbetterspecs/evenbetterspecs.github.io/discussions/8">Discuss this guideline</a>
 </article>