enable emoji on website; enable normal ul elements

grouped these together:

- Site can now use emoji :party:
- Using the `.single-column` class will render a `ul` element as a "normal" list
- Suppress the warning about `text` being an unknown language coming out of 11ty/Prism/markdown-it

Ref: #4198

.eleventy.js

@@ -31,6 +31,8 @@ module.exports = function(eleventyConfig) {
 
   markdown.use(require('markdown-it-prism'));
 
+  markdown.use(require('markdown-it-emoji'));
+
   eleventyConfig.setLibrary('md', markdown);
 
   return {

.markdownlint.json

@@ -6,5 +6,6 @@
   "first-header-h1": false,
   "first-line-h1": false,
   "commands-show-output": false,
-  "single-h1": false
+  "single-h1": false,
+  "fenced-code-language": false
 }

docs/css/style.css

@@ -171,6 +171,13 @@ ul {
   padding: 0 15px;
 }
 
+ul.single-column,
+ul.single-column > li > ul {
+  column-count: 1;
+  margin-top: 0;
+  padding-right: 0;
+}
+
 ul li {
   border-bottom: 1px solid #eee;
   break-inside: avoid;
@@ -179,6 +186,17 @@ ul li {
   padding: 5px 0;
 }
 
+ul.single-column li,
+ul.single-column li > ul > li {
+  list-style: disc;
+  padding: 0;
+  border-bottom: 0;
+}
+
+ul.single-column li > ul > li {
+  list-style: circle;
+}
+
 code {
   font: 14px monaco, monospace;
   line-height: 1.8;