Fix typos in Update custom-resources.md

[DamianEdwards]

Fixes some minor issues in the custom resources doc observed while watching https://www.youtube.com/watch?v=4rVrR9haWlg

Summary

Describe your changes here.

Fixes #Issue_Number (if available)

---

Internal previews

📄 File	🔗 Preview link
docs/extensibility/custom-resources.md	Create custom resource types for .NET Aspire

[IEvangelist]

Thank you so much for your video @peterj, it was really helpful in helping identify a few opportunities for improvement!

[joperezr]

Just a note, technically I don't think it needs to match the Aspire workload, but instead the version of Aspire.Hosting.AppHost package reference in the AppHost project.

[joperezr]

(which ideally, both that and the workload would be the same version, but that is not always the case)

[IEvangelist]

That's what is being added... it will always match itself 🤣. The .NET CLI command is adding a package reference to version 8.0.0.

[joperezr]

Right after the project is created, then yes, they will match of course. But think about the scenario where I have one workload version, create the project and push it to a repo, and you have a different workload version and pull the repo, and want to work on a client library (hosting package). This is what I meant that you'll want to match the version of the packagereference (which will match my workload as opposed to yours) instead of the version of your workload.

[mitchdenny]

We'll need to change the versions back in a few days ;)

[DamianEdwards]

Shhhhh