docs: formatting in page titles is incorrectly used in og:title tag

[pixelastic]

When using custom markdown formatting in page titles, this formatting is propagated to the og:title tag.

Such formatting should be stripped, so the og:title is clean, while still allowing formatting in titles.

Example:

---
title: Spread `INSERT`s among cluster shards
---

This will add the backticks in the og:title, while converting them to <code> in a title.

I don't think this is something that should be locally fixed, but we should rather submit a PR upstream to https://github.com/nuxt/content/tree/v1/packages/theme-docs