fix: crawl hrefs that start with config.prerender.origin

[LorisSigrist]

Closes #12271

Until now the crawler would not recoginze links that start with the value of config.prerender.origin as internal links & would not crawl them. This PR fixes that.

For example: A link <a href="https://my-site/base/some-page" would not be crawled, even if prerender.origin was set to https://my-site in svelte.config.js.

This is important since <link rel="alternate" requires links to be absolute URIs that include the protocol, so until now it was impossible for the crawler to discover pages that were linked to in valid <link rel="alternate" links.

---

Please don't delete this checklist! 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. In many cases, features are absent for a reason. For large changes, please create an RFC: https://github.com/sveltejs/rfcs
• This message body should clearly illustrate what problems it solves.
• Ideally, include a test that fails without this PR but passes with it.

Tests

• Run the tests with pnpm test and lint the project with pnpm lint and pnpm check

Changesets

• If your PR makes a change that should be noted in one or more packages' changelogs, generate a changeset by running pnpm changeset and following the prompts. Changesets that add features should be minor and those that fix bugs should be patch. Please prefix changeset messages with feat:, fix:, or chore:.

Edits

• Please ensure that 'Allow edits from maintainers' is checked. PRs without this option may be closed.

[changeset-bot]

🦋 Changeset detected

Latest commit: 6533d74

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@sveltejs/kit	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[benmccann]

thanks!!