Refine content collection warnings

[bholmesdev]

Changes

Starlight users have struggled with a warning message for the i18n collection:

[WARN] [content] The i18n collection is defined but no content/i18n folder exists in the content directory. Create a new folder for the collection, or check your content configuration file for typos.

This warning was initially added to prevent typos between your configured collection name and the actual directory name. Even so, warning logs are easily lost during development. This GitHub discussion describes hours lost due to this.

What we want is some indicator during development that there's a mismatch, without excessive console warnings. We landed here:

1. We should remove the warning for a configured collection that lacks a directory.
2. Add type generation for a configured collection even when the directory doesn't exist. As that discussion above notes, they may have caught their typo sooner if generated types included their misconfigured directory. "Huh, why do I see both article and articles in my intellisense? Ah, probably a typo."

Code changes

• Remove "may be a typo" warning when a configured collection lacks a matching directory
• Respect configured collections in generated types, even when a matching directory DNE

Testing

N/A - type change only

Docs

N/A

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Latest commit: 9d34d66

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[github-actions]

This PR is blocked because it contains a minor changeset. A reviewer will merge this at the next release if approved.

[delucis]

Not super familiar with the type gen code, but I agree with the idea here and it looks like the right pieces have been added and removed as far as I can tell — thanks for tackling @bholmesdev!

[sarah11918]

YAY BEN! 🥳

For the sake of a visible checkmark, docs is approving!

Merge day