add anchor icon to heading anchors

layouts/_default/single.html

@@ -28,7 +28,11 @@
   {{ end }}
 
   <div class="post-content">
-    {{ .Content }}
+  {{- with .Content -}}
+      <div>
+        {{ . | replaceRE "(<h[1-9] id=\"([^\"]+)\".+)(</h[1-9]+>)" `${1}<a href="#${2}" class="hanchor" ariaLabel="Anchor"> 🔗&#xFE0E;</a> ${3}` | safeHTML }}
+      </div>
+      {{- end -}}
   </div>
   {{ if or .NextInSection .PrevInSection }}
   <div class="pagination">