Docs: Fix dead links and invalid hashes

[julien-deramond]

Description

I've spotted a dead link while browsing the documentation, and since I knew that you're using Starlight, I tried to install and execute starlight-links-validator.

The primary goal of this PR is to fix the dead links and invalid hashes, but it also includes a possible enhancement for the project by using starlight-links-validator.

Installing starlight-links-validator

The first commit of this PR (8726ef1) shows how to install starlight-links-validator.

1. If you don't want to install it for whatever reason, I can remove this commit. Just wanted to show you how it works.
2. ⚠️ If you'd like to keep starlight-links-validator, there will be a fix to do in this PR as I had to comment a line in docs/src/remark-playground.ts. I haven't especially tried to fix this properly, I preferred to know before whether you would like to include starlight-links-validator in your build :)

Fix dead links and invalid hashes in the doc

Here's the output of running npm run docs:build with starlight-links-validator enabled in the project:

13:46:07 [ERROR] ✗ Found 36 invalid links in 8 files.
13:46:07 ▶ info/package_structure/
13:46:07   └─ /references/info/tokens - invalid link
13:46:07 ▶ info/tokens/
13:46:07   └─ /reference/hooks/transforms#attributecti - invalid hash
13:46:07 ▶ reference/hooks/formats/
13:46:07   ├─ predefined - relative link
13:46:07   ├─ predefined - relative link
13:46:07   ├─ /reference/hooks/filter - invalid link
13:46:07   ├─ /reference/hooks/filter - invalid link
13:46:07   ├─ predefined/#cssvariables - relative link
13:46:07   ├─ predefined/#scssvariables - relative link
13:46:07   ├─ predefined/#lessvariables - relative link
13:46:07   ├─ predefined/#androidresources - relative link
13:46:07   ├─ predefined/#composeobject - relative link
13:46:07   ├─ predefined/#ios-swiftclassswift - relative link
13:46:07   ├─ predefined/#flutterclassdart - relative link
13:46:07   └─ /reference/hooks/formats#fileheader - invalid hash
13:46:07 ▶ reference/hooks/transform-groups/predefined/
13:46:07   ├─ /reference/hooks/transforms/predefined#sizeflutterremToDouble - invalid hash
13:46:07   └─ /reference/hooks/transforms/predefined#sizeflutterremToDouble - invalid hash
13:46:07 ▶ reference/hooks/formats/predefined/
13:46:07   ├─ #references-in-output-files - invalid hash
13:46:07   ├─ #references-in-output-files - invalid hash
13:46:07   ├─ #references-in-output-files - invalid hash
13:46:07   ├─ #references-in-output-files - invalid hash
13:46:07   ├─ #references-in-output-files - invalid hash
13:46:07   ├─ #references-in-output-files - invalid hash
13:46:07   ├─ #references-in-output-files - invalid hash
13:46:07   ├─ #references-in-output-files - invalid hash
13:46:07   ├─ #references-in-output-files - invalid hash
13:46:07   └─ #references-in-output-files - invalid hash
13:46:07 ▶ reference/hooks/transforms/predefined/
13:46:07   └─ /info/tokens#category-type-item - invalid hash
13:46:07 ▶ reference/api/
13:46:07   ├─ /references/hooks/file-headers - invalid link
13:46:07   ├─ /references/hooks/formats#creating-formats - invalid link
13:46:07   └─ /reference/hooks/transform_groups - invalid link
13:46:07 ▶ reference/config/
13:46:07   ├─ /reference/tokens - invalid link
13:46:07   ├─ /reference/using_the_cli - invalid link
13:46:07   ├─ /reference/using_the_cli - invalid link
13:46:07   ├─ /reference/using_the_npm_module - invalid link
13:46:07   ├─ /reference/hooks/format#references-in-output-files - invalid link
13:46:07   └─ /reference/hooks/formats#customfileheader - invalid hash

Based on these results, I tried to find the correct target URLs in b672395. Hope I haven't made too many mistakes 😬

Fix invalid hashes in the library

Finally, one of these invalid hashes was also in the comments of the library, so has been fixed along the way via 94e3a38.

Final words

In the end, this PR gathers different elements.
Based on your feedback, I can remove/modify the commits, or split the PR.
Please note that I haven't added any changesets, waiting for a first feedback on how to proceed :)

---

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

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[jorenbroekema]

Approved and fixed the type issues in the remark-playground file, then squashed the commits into 1.

Thanks for the contribution :)