Add a 'name in series' helper to re-use logic

Signed-off-by: Danila Fedorin <danila.fedorin@gmail.com>

layouts/partials/serieslink.html

@@ -3,13 +3,9 @@
     {{ if eq .direction "previous" }}{{ partial "icon.html" "chevrons-left" }}{{ end }}
     <div class="title-subtitle">
       {{ title .direction }} in Series
-      {{ $divider := .term.Params.divider }}
-      {{ if (and $divider (strings.Contains .page.Title $divider)) }}
-      {{ $rest := after 1 (split .page.Title $divider) }}
-      <div class="title">{{ delimit $rest $divider }}</div>
-      {{ else }}
-      <div class="title">{{ .page.Title }}</div>
-      {{ end }}
+      {{ $scratch := newScratch -}}
+      {{- partial "nameinseries.html" (dict "page" .page "scratch" $scratch) -}}
+      <div class="title">{{ $scratch.Get "name" }}</div>
     </div>
     {{ if eq .direction "next" }}{{ partial "icon.html" "chevrons-right" }}{{ end }}
   </a>