Theme: Keep current event for 6 hours after start date

Events are shown in the "Neuigkeiten" section until their start date has been reached.
As we deploy quite often, this means, that the currently running event will disappear when it's still going.
As we don't know the end date, just show them for 6 more hours.

themes/ccchh/layouts/index.html

@@ -5,7 +5,8 @@
     </div>
 
     {{- $events := where (.Site.GetPage "blog").Pages ".Params.categories" "event" }}
-    {{- $upcoming := where $events ".Params.date" "ge" now }}
+    {{- $lookback := time.ParseDuration "-6h" }}
+    {{- $upcoming := where $events ".Params.date" "ge" (time.Now.Add $lookback) }}
     {{ if $upcoming }}
     <div class="announcements">
       <h2 id="neuigkeiten" class="on-hover-trg">Neuigkeiten <a href="#neuigkeiten" class="on-hover"><i class="fa-solid fa-link small"></i></a></h2>