start work to implement a 'read further' separator for the links

Problems: The JS based selectors lead to strange results as in the top5 list there might me no items in the first 5 left. Perhaps a JS-only solution might make sense in the long run

content/links.md

@@ -13,7 +13,7 @@ You can click on the buttons to select only links with the given language or top
 
 A selection of my presentations and radio shows I participated in. By clicking on the respective icons you can watch the video recording, access the slides and listen to the audio recording.
 
-{{< links type="av" >}}
+{{< links type="av" limit="5" >}}
 
 ## Appearance in Media {#media}
 

themes/hugo-sustain/layouts/shortcodes/links.html

@@ -2,9 +2,22 @@
 {{- $data := .Site.Data.links -}}
 {{- if $type -}}
   {{- $data = where $data "type" $type -}}
-{{ end }}
+{{- end }}
+{{- $data = sort $data "date" "desc" }}
+{{- $datalen := $data | len }}
+{{- $limit := (.Get "limit" | default -1) | int }}
+{{- $limit_trigger := false }}
 <ul>
-{{- range sort $data "date" "desc" }}
+{{- range $index, $val := $data }}
+  {{- /* Evaluate limit */}}
+  {{- if eq $index $limit }}
+    {{- $limit_trigger = true }}
+    <details><summary>Show more</summary>
+  {{- end }}
+  {{- $tags := slice -}}
+  {{- range $val.lang }}{{ $tags = $tags | append . }}{{ end -}}
+  {{- range $val.tags }}{{ $tags = $tags | append . }}{{ end -}}
+
   {{- $tags := slice -}}
   {{- range .lang }}{{ $tags = $tags | append . }}{{ end -}}
   {{- range .tags }}{{ $tags = $tags | append . }}{{ end -}}
@@ -23,4 +36,7 @@
     {{ range $tags }}&nbsp;<span class="label label-success">{{ . }}</span>{{ end -}}
   </li>
 {{ end }}
+{{- if $limit_trigger }}
+  </details>
+{{- end }}
 </ul>