fix: rewrite smart quotes logic

[Ocean-OS]

Closes #781. I'm not entirely sure on what first does, or if I'm using it correctly in the logic, but everything else should be good.

Before submitting the PR, please make sure you do the following

• It's really useful if your PR references an issue where it is discussed ahead of time.
• Prefix your PR title with feat:, fix:, chore:, or docs:.
• This message body should clearly illustrate what problems it solves.

[vercel]

@Ocean-OS is attempting to deploy a commit to the Svelte Team on Vercel.

A member of the Team first needs to authorize it.

[vercel]

The latest updates on your projects. Learn more about Vercel for Git ↗︎

Name	Status	Preview	Updated (UTC)
svelte-dev	❌ Failed (Inspect)		Aug 4, 2025 3:55am

[eltigerchino]

I'm not entirely sure on what first does

I think first is used to tell if we're in a complete sentence or substring. It's only being used when we're processing the shiki tokens token by token so that a substring such as example" that's part of a bigger string "an example" will get the right quotation direction.

[eltigerchino]

The new approach seems to error in cases where a title has a single quote character such as https://svelte.dev/docs/kit/images#Vite's-built-in-handling . It changes the single quote to a left single quote when it should be a right single quote as it is currently.

Possible edge cases we should account for:
a) Vite's built-in handling (right single quote)
b) "Vite's built-in handling" (smart double quotes with right single quote)
c) <script lang="ts"> (smart double quotes but in a single word)

I wonder if it's worth adding a unit test for this but I can see we don't have Vitest set up despite having a test command in the root package.json