Use callout without custom Jekyll plugin.

_plugins/callout.rb

@@ -1,28 +0,0 @@
-# Source: https://stackoverflow.com/questions/19169849/how-to-get-markdown-processed-content-in-jekyll-tag-plugin
-
-module Jekyll
-  module Tags
-    class CalloutTag < Liquid::Block
-
-      def initialize(tag_name, type, tokens)
-        super
-        type.strip!
-        if %w(info danger warning).include?(type)
-          @type = type
-        else
-          puts "#{type} callout not supported. Defaulting to info"
-          @type = "info"
-        end
-      end
-
-      def render(context)
-        site = context.registers[:site]
-        converter = site.find_converter_instance(::Jekyll::Converters::Markdown)
-        output = converter.convert(super(context))
-        "<div class=\"bd-callout bd-callout-#{@type}\">#{output}</div>"
-      end
-    end
-  end
-end
-
-Liquid::Template.register_tag('callout', Jekyll::Tags::CalloutTag)