try Hugo highlight

Author: sarahsanders-docker

content/contribute/file-conventions.md

@@ -37,8 +37,8 @@ following keys are supported. The title, description, and keywords are required.
 Here's an example of a valid (but contrived) page metadata. The order of
 the metadata elements in the front matter isn't important.
 
-```txt
---- #example front matter
+{{< highlight plaintext >}}
+---
 description: Instructions for installing Docker Engine on Ubuntu
 keywords: requirements, apt, installation, ubuntu, install, uninstall, upgrade, update
 title: Install Docker Engine on Ubuntu
@@ -54,8 +54,8 @@ aliases:
 - /install/linux/ubuntu/
 - /installation/ubuntulinux/
 toc_max: 4
---- # end front matter
-```
+---
+{{< /highlight >}}
 
 ## Body