PR Checklist

• Addresses an existing open issue:fixesDocs: Add blog post & revamped docs for parserOptions.projectService #7350
• That issue was marked asaccepting prs
• Steps inContributing were taken

Overview

Adds a blog post that describes usingparserOptions.projectService (what we previously calledparserOptions.EXPERIMENTAL_useProjectService). The flow is roughly:

1. Introduction: the old situation & an overview of the blog post
2. Configuration: how to switch over & replace traditional config kludge
3. Predictability: benefits of the new API & not havingtsconfig.eslint.jsons
4. Scalability: project references support! 🙌
5. Performance: noting that it's theoretically faster, but not always -- and that that's being treated as a bug
6. Next steps: feedback, the standalone package, and hope for typescript-go

This was previously blocked on:

• feat(typescript-estree): add allowDefaultProjectForFiles project service allowlist option #7752: for locking down how an"additional files / to be given default program type info" should look
• feat: add support for flat configs #7935: for example flat configs in the post
• Creating a set of example configs on a new, not-yet-createdhttps://github.com/typescript-eslint/examples
• Enhancement: Finalize naming for EXPERIMENTAL_useProjectService #9004
• Creating and running performance comparisons ona new, not-yet-createdhttps://github.com/typescript-eslint/project-apis-performance-comparisonhttps://github.com/typescript-eslint/performance

This previously had a lot more content on single-run mode and performance comparisons. Both are removed for a more streamlined blog post.

💖