The `title_meta` field in doc front matter is ignored

[MisterFISHUP]

Have you read the Contributing Guidelines on issues?

• I have read the Contributing Guidelines on issues.

Prerequisites

• I'm using the latest version of Docusaurus.
• I have tried the npm run clear or yarn clear command.
• I have tried rm -rf node_modules yarn.lock package-lock.json and re-installing packages.
• I have tried creating a repro with https://new.docusaurus.io.
• I have read the console error message carefully (if applicable).

Description

The title_meta field, as documented in the docs, should allow overriding frontMatter.title for SEO purposes. However, it doesn't work for doc pages, while it does work correctly for blog posts.

Reproducible demo

No response

Steps to reproduce

Create a new doc page with the following front matter

---
title: Visible Title
title_meta: SEO Title
---

Check the page's title in the browser or inspect the meta tags.

Expected behavior

The title should use title_meta instead of title, as described in the docs:

Permits to override frontMatter.title when the displayed title and SEO title should be different.

Actual behavior

The title_meta field is ignored, and the <title> tag or og:title still use title instead.

Your environment

No response

Self-service

• I'd be willing to fix this bug myself.

[slorber]

Superseded by #10916