feat: add optional breadcrumb trail

layouts/docs/single.html

@@ -3,7 +3,7 @@
 		<div class="col-lg-5 col-xl-4 docs-sidebar">
 			<nav class="docs-links" aria-label="Main navigation">
 				{{ partial "sidebar/docs-menu.html" . }}
-			</nav>        
+			</nav>
 		</div>
 		{{ if ne .Params.toc false -}}
 		<nav class="docs-toc d-none d-xl-block col-xl-3" aria-label="Secondary navigation">
@@ -15,6 +15,15 @@
 		{{ else -}}
 		<main class="docs-content col-lg-11 col-xl-9 mx-xl-auto">
 		{{ end -}}
+			{{ if .Site.Params.options.breadCrumb -}}
+				<!-- https://discourse.gohugo.io/t/breadcrumb-navigation-for-highly-nested-content/27359/6 -->
+				<nav aria-label="breadcrumb">
+					<ol class="breadcrumb">
+						{{ partial "main/breadcrumb" . -}}
+						<li class="breadcrumb-item active" aria-current="page">{{ .Title }}</li>
+					</ol>
+				</nav>
+			{{ end }}
 			<h1>{{ .Title }}</h1>
 			<p class="lead">{{ .Params.lead | safeHTML }}</p>
 			{{ partial "main/headline-hash.html" .Content }}