fix single-fetch types for functions that return unions

[pcattori]

Supercedes #9834
Fixes #9826 , #9998

[changeset-bot]

🦋 Changeset detected

Latest commit: 6edf036

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

This PR includes changesets to release 16 packages

Name	Type
@remix-run/server-runtime	Patch
@remix-run/cloudflare	Patch
@remix-run/deno	Patch
@remix-run/dev	Patch
@remix-run/node	Patch
@remix-run/react	Patch
@remix-run/testing	Patch
@remix-run/cloudflare-pages	Patch
@remix-run/cloudflare-workers	Patch
@remix-run/architect	Patch
@remix-run/express	Patch
@remix-run/serve	Patch
create-remix	Patch
remix	Patch
@remix-run/css-bundle	Patch
@remix-run/eslint-config	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[pcattori]

@michaelgmcd I tried to checkout your #9834 PR, but gh repo checkout was struggling with it (probably due to merge conflicts? 🤷‍♂️) so I adapted your work in this PR and added you as a co-author of the commit so you get credit. Thanks for your work on this!

[github-actions]

🤖 Hello there,

We just published version 2.12.1-pre.0 which includes this pull request. If you'd like to take it for a test run please try it out and let us know what you think!

Thanks!

[github-actions]

🤖 Hello there,

We just published version 2.12.1 which includes this pull request. If you'd like to take it for a test run please try it out and let us know what you think!

Thanks!