add structured data for breadcrumb nav

https://developers.google.com/search/docs/data-types/breadcrumb

layouts/partials/templates/schema_json.html

@@ -16,7 +16,46 @@
   ]
 }
 </script>
-{{- else if .IsPage }}
+{{- else if (or .IsPage .IsSection) }}
+{{/* BreadcrumbList */}}
+{{- $url := replace .Parent.Permalink ( printf "%s" .Site.BaseURL) "" }}
+{{- $lang_url := replace $url ( printf "%s" .Lang) "" }}
+{{- $bc_list := (split $lang_url "/")}}
+
+{{- $scratch := newScratch }}
+<script type="application/ld+json">
+{
+  "@context": "https://schema.org",
+  "@type": "BreadcrumbList",
+  "itemListElement": [
+  {{- range $index, $element := $bc_list }}
+
+    {{- $scratch.Add "path" (printf "%s/" $element ) | safeJS }}
+    {{- $bc_pg := $.Site.GetPage ($scratch.Get "path") -}}
+
+    {{- if (and ($bc_pg) (gt (len . ) 0))}}
+    {{- if (and $index)}}, {{end }}
+    {
+      "@type": "ListItem",
+      "position": {{ add 1 $index  }},
+      "name": {{ $bc_pg.Name }},
+      "item": {{ $bc_pg.Permalink | safeHTML }}
+    }
+    {{- end }}
+
+  {{- end }}
+  {{- /*  self-page addition  */ -}}
+  {{- if $bc_list }}, {{end }}
+    {
+      "@type": "ListItem",
+      "position": {{len $bc_list}},
+      "name": {{ .Name }},
+      "item": {{ .Permalink | safeHTML }}
+    }
+  ]
+}
+</script>
+{{- if .IsPage }}
 <script type="application/ld+json">
 {
   "@context": "https://schema.org",
@@ -75,4 +114,6 @@
   }
 }
 </script>
+{{ end }}{{/* .IsPage end */}}
+
 {{ end }}