feat: more information when hydration fails

[Rich-Harris]

In the case of an invalid child element, we already get information about the parent and the child, but in other cases where a mismatch could occur you're pretty much on your own.

This adds a bit more context to hydration_mismatch warnings — 'The error occurred near ...'

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🦋 Changeset detected

Latest commit: d9712df

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

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