Make all headings in blog posts linkable

It's nice to be able to link certain sections of a blog post
when trying to share ideas.

Followed the steps [here](https://blog.briandrupieski.com/generate-anchors-in-jekyll-blog-post)
to autogenerate links next to headers in posts

jquery-3.4.1.min.js is from [here](https://code.jquery.com/jquery-3.4.1.min.js)
anchor.min.js is from [here](https://github.com/bryanbraun/anchorjs/blob/4.2.0/anchor.min.js)

Author: chrisc11

_layouts/post.html

@@ -2,6 +2,7 @@
 layout: default
 ---
 <article id="post-page">
+    <script src="/js/anchor.min.js"></script>
 	<h2>{{ page.title }}</h2>		
 	<time datetime="{{ page.date | date_to_xmlschema }}" class="by-line">{{ page.date | date_to_string }}</time>
 	<div class="content">
@@ -29,5 +30,7 @@ <h2>{{ page.title }}</h2>
         d.src = DiscourseEmbed.discourseUrl + 'javascripts/embed.js';
         (document.getElementsByTagName('head')[0] || document.getElementsByTagName('body')[0]).appendChild(d);
     })();
+    anchors.options.visible = 'hover';
+    anchors.add('.post-content > h1, h2, h3, h4, h5, h6');
 </script>