Improve errors for invalid IDs in content collections

[louisescher]

Changes

This PR improves the error messages for IDs in content collections.

IDs in content collections have always been required to be strings, however the error message when passing (for example) a number would look like this:

[ContentLoaderInvalidDataError] todos entry is missing an ID.
Entry missing ID:
{
  "userId": 1,
  "title": "delectus aut autem",
  "completed": false
}

This would even be the case if the original entry looked like this:

{
  "userId": 1,
  "id": 1,
  "title": "delectus aut autem",
  "completed": false
}

This PR changes these error messages so that they throw a new and more verbose AstroError based on the Zod validation.
For this to work, the parsing logic had to be moved from the functions return type schema to an external schema, and the validation had to be moved into the simpleLoader function itself due to performance issues with Zod when using z.function().returns(...).

Testing

The changes in this PR should be covered by the existing tests as no behavior has been added or changed.

Docs

/cc @withastro/maintainers-docs for feedback!

A docs PR has been made here

[changeset-bot]

🦋 Changeset detected

Latest commit: 99397b0

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

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[codspeed-hq]

CodSpeed Performance Report

Merging #12892 will not alter performance

_{Comparing louisescher:verbose-id-errors (99397b0) with main (f00c2dd)}

Summary

✅ 6 untouched benchmarks

[ascorbic]

Great! A definite improvement. Could you add a test, checking that it throws the right error when passed a number for ID? Also can you add a patch changeset? Thanks!

[louisescher]

@ascorbic Will do!

[sarah11918]

Just commenting on the error message for docs in general! I indicated a couple of places (but would apply throughout if appropriate) where this might be targeted specifically to IDs, if that is in fact what this is solely focused on.

I'll leave it to y'all, but just pointing out that if it makes sense to be more specific, it's often more helpful and informative to the user! (Also easier to come up with another error name in the case of a different kind of "invalid" result. 😄 )