Fix pattern matching for @ encoded routes

[trmcnvn]

Prior to this PR, if you had a route that started with an encoded @ symbol, it would not recognize the route because it split it based on the decoded @ symbol which is used for named layouts. This PR moves the decoding until after the split.

In the following setup, /@foo would not be accessible.

routes/
  %40foo/
    +page.svelte
  +page.svelte

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🦋 Changeset detected

Latest commit: e3d61e7

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

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[Rich-Harris]

this is excellent, thanks so much!