Build errors due to false positive missing links containing umlauts

[janosh]

Describe the bug

Also not pictured: tests of funky IDs that involve URL or HTML encoding. No idea if that works in this branch currently but either way it needs tests.

Answer to @Rich-Harris' question in #7375 is no. Doesn't handle umlauts.

The following pages contain links to /#%C3%BCberblick, but no element with id="%C3%BCberblick" exists on /

where actually <a href="#überblick" aria-hidden="true"> exists on that page.

Also, maybe the error message could suggest "Set config.kit.prerender.handleMissingId = 'warn' to disable this error" so people don't have to go hunting through docs/git history.

Reproduction

<h2 id="überblick">
  Überblick
  <a href="#überblick" aria-hidden="true"></a>
</h2>

npm run build in this StackBlitz.

Logs

No response

System Info

StackBlitz

Severity

serious, but I can work around it

Additional Information

No response