Issue #3495689 by grimreaper: Views summary default styling

Closes #3495689

templates/views/views-view-summary-include.html.twig

+{#
+/**
+ * @file
+ * Default theme implementation to display a list of summary lines.
+ *
+ * Available variables:
+ * - rows: The rows contained in this view.
+ *   Each row contains:
+ *   - url: The summary link URL.
+ *   - link: The summary link text.
+ *   - count: The number of items under this grouping.
+ *   - attributes: HTML attributes to apply to each row.
+ *   - active: A flag indicating whether the row is active.
+ * - options: Flags indicating how the summary should be displayed.
+ *   This contains:
+ *   - count: A flag indicating whether the count should be displayed.
+ *
+ * @see template_preprocess_views_view_summary()
+ *
+ * @ingroup themeable
+ */
+#}
+{{ row.link }}
+{% if options.count %}
+  <span class="badge text-bg-primary rounded-pill">
+  {{ row.count }}
+  </span>
+{% endif %}