Make sure the docs folder is up to date with new structure

[stevenjmesser]

What

Check that the documentation inside the repository (in docs) are up to date with the new repository structure, especially:

• the docs for releasing to npm
• the docs for pushing a pre-release as a branch on Github
• but also all the other pieces of documentation in there

Why

We're making substantial changes to our repository structure ahead of v5. We need to ensure that our docs reflect these changes so they can help future us and contributors appropriately.

Pushing a pre-release branch, especially, is really helpful for contributors as it allows them to install their changes as an npm package (without releasing to npm)

Who needs to work on this

Developers, Tech writers?

Who needs to review this

Developers, Tech writers?

Done when

We've reviewed

Preview Give feedback

1. The npm release docs (both from main and from support branch)
2. The docs for making a pre-release on Github
3. The rest of the docs

[romaricpascal]

Closed by #3975 (the PR was referencing the wrong issue). The docs have been reviewed, but we'll open issues should any problem arise when running our first pre-releases.