Give endnotes a heading

See #260

Author: philwareham

src/assets/js/main.js

@@ -9,6 +9,7 @@
     // Load objects as variables.
 
     var code = document.querySelectorAll('pre code'),
+        endnote = document.querySelector('.footnotes'),
         navmenu = document.getElementById('site-navigation');
 
     // Syntax highlighting, via 'Prism'.
@@ -26,6 +27,12 @@
         Prism.highlightAll();
     }
 
+    // Inject a heading into endnotes regions.
+
+    if (endnote) {
+        endnote.insertAdjacentHTML('afterbegin', '<h4>Endnotes</h4>');
+    }
+
     // Responsive navigation menu.
 
     if (navmenu) {