Do not unique-by-series when a flag is set

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

layouts/partials/uniquebyseries.html

@@ -3,7 +3,7 @@
 {{- $tmpScratch := newScratch -}}
 {{- range $post := (where (where site.Pages.ByDate.Reverse "Section" "blog") ".Kind" "!=" "section") -}}
 {{- $term := index ($post.GetTerms "series") 0 -}}
-{{- if $term -}}
+{{- if (and $term (not ($term.Param "donotunique"))) -}}
 {{- if not ($tmpScratch.Get $term.Permalink) -}}
 {{- $tmpScratch.Set $term.Permalink true -}}
 {{- $scratch.Add "pages" $post -}}