Testing backticks in front matter title on two HTML pages

[dipikabh]

Description

For standardizing our titles on reference pages, backtick support has been added in mdn/rari#552, which is now available in mdn/content.

In this PR, I'm trying out the backticks on two reference pages in HTML.

rari is correctly outputting titleHTML in the JSON:

• "titleHTML": "<code>is</code> HTML global attribute"
• "titleHTML": '<code>&lt;input type="number"&gt;</code> HTML attribute value'

Additional details

fred still needs to be updated to read titleHTML from rari's output and render it in page <h1>.
Also, after fred starts rendering <code> tags in the title, they'd need to be styled appropriately.

Meanwhile, title updates need not be blocked by fred work and can proceed in parallel.

Related issues and pull requests

• Reference page titles are not consistent and need improvements #39894
• [PROJECT] HTML & CSS reference page title standardization mdn#811

[github-actions]

Preview URLs (2 pages)

• /en-US/docs/Web/HTML/Reference/Elements/input/number
• /en-US/docs/Web/HTML/Reference/Global_attributes/is