improve template

Author: khvn26

src/common/core/templates/docgen-metrics.md

@@ -1,8 +1,14 @@
-# Prometheus metrics
+---
+title: Metrics
+---
+
+## Prometheus
 
 Flagsmith exports Prometheus metrics described below.
 {% for metric in flagsmith_metrics %}
-## `{{ metric.name }}` {{ metric.type }}
+### `{{ metric.name }}`
+
+{{ metric.type|title }}.
 
 {{ metric.documentation }}