Attributes are not rendered correctly

[kosabogi]

Describe the bug

The variables in the Machine Learning book are not rendering correctly when building the site.
For example, in the "What is Elastic Machine Learning" section, it appears as "What is Elastic {{ml-app}}?"
This issue affects all variables in the menu bar.

Expected behavior

The variables should display their corresponding values.

Steps to reproduce

No response

Tooling

• docs-builder
• migration tooling
• I'm not sure

[colleenmcginnis]

Also in the title text for collapsible blocks:

Local link