\ did not exist in other headings, so I removed it (not sure what this escaping would be useful for)

I saw this in other places as well. Might've been an artifact from copying the original doc into markdown.

Actually, I think the mistake is here. The changelog title is level 1 and then we skip level 2. "All Changes" below does it right and is at level 2. So I guess we need to dedent "New Features", "Breaking Changes", "Deprecations", "TypeScript changes", and "Notable Changes" instead.

That's what I did in the release: https://github.com/facebook/react/releases/tag/v19.0.0

I see what you mean, done this in 4487a65.

We still have a somewhat incorrect document structure though, and it’s because version numbers have now got the same heading levels as New features, All changes. Here is the outline of CHANGELOG.md:

main

↑ Types of change and areas are mixed

This PR before review

↑ Nesting is semantically meaningful, but areas are at level 4 while they are often at level 3 in previous versions

This PR after 4487a65

↑ Version and types of change are at the same level

So we can imagine software like Renovate bot scanning the mardown and detecting v19.0.0 changelog only between these lines:

As a permanent solution, we can switch to this in the whole markdown in a follow-up:

# 1.2.3 (Jan 1, 1970)

## Type of change (e.g. New Features) – can be skipped in patch releases

### Area (e.g. React DOM Client) – always at level 3

Happy to open a separate PR if you see value in this kind of cleanup.

Alternatively, we could do this:

# React.js Changelog

## 1.2.3 (Jan 1, 1970)

### Type of change (e.g. New Features) – can be skipped in patch releases

#### Area (e.g. React DOM Client) – always at level 4

Right, in the release it starts at level on and in the markdown at level 2