Merge #170: The completion hint reaches the owner, and decides nothing

# Conflicts:
#	backend/internal/web/admin_series_detail.go

backend/internal/web/templates/series-detail.html

@@ -47,6 +47,7 @@
 {{else}}
 <div class="dform">
   <div class="field"><button type="button" class="ghost" onclick="document.getElementById('confirm-finish').hidden = false">Finish</button></div>
+  {{if .SiteCompleted}}<p class="hint">{{.SiteCompleted}}</p>{{end}}
   <div class="confirm-row calm" id="confirm-finish" role="group" aria-live="polite" hidden>
     <span>Mark this Series finished?</span>
     <div>