Description

• This PR fixes mapping between Astro.params and content collection entries for entries which have a filename with non-normalized composition.
• For example, اللُّغَةُ-الْعَرَبِيَّةُ/الْآجُرُومِيَّةُ.md uses a mix of precomposed and decomposed diacritics. However, Astro’s router always normalizes URL parameters, which led to a mismatch between Starlight’s routes and Astro’s params, resulting in a 404 for a file with that name.
• Starlight’s internal route map now normalizes slugs to match Astro’s behaviour.
• One issue this can’t fix is differences between the composition of a user-authored link in Markdown and the actual built URL. For example, this change fixes the 404 issue but this means the output HTML file name is now differently composed than the input Markdown file name. If a user-authored link uses the same composition as the input file name, that will still be a 404, because it doesn’t match the output composition. Long story short, maybe people should avoid risking diacritics in URLs 😅 But at least we’re now matching Astro’s behaviour so there is a path to doing this without manually normalizing your file names.

N.B. The test changes in this PR look big because I wrapped existing tests in a describe() block, but apart from that those haven’t actually changed. I just renamed components.test.ts to basics.test.ts to match and reuse the basics fixture and avoid spinning up a new fixture just for this.