fix: do not use liquid (#22756)

Author: ArthurFlag

content/contribute/file-conventions.md

@@ -37,7 +37,7 @@ 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.
 
-```liquid
+```text
 ---
 description: Instructions for installing Docker Engine on Ubuntu
 keywords: requirements, apt, installation, ubuntu, install, uninstall, upgrade, update
@@ -70,7 +70,7 @@ Splitting long lines (preferably up to 80 characters) can make it easier to prov
 If you want to add an entry to the sidebar, but you want the link to point somewhere else, you can use the `sidebar.goto` parameter.
 This is useful in combination with `build.render` set to `always`, which creates a pageless entry in the sidebar that links to another page.
 
-```md
+```text
 ---
 title: Dummy sidebar link
 build: