macros: fix diagnostics of last statement

[icedrocket]

This change prevents rust-analyzer from incorrectly analyzing the last statement of the main function as a Builder::new_* method.

Fixes #5518

It was a combination of coincidences that led me to think the issue was resolved.

[Darksonn]

This PR is simpler than the abandoned #5619. What is the difference?

[icedrocket]

I think the problem was caused by the presence of unspanned tokens between spanned tokens. After removing the span hole, it was displayed correctly in the IDE.

[Darksonn]

Okay, if this works for you in your IDE, then that's good enough for me.

[Darksonn]

Thanks!

[icedrocket]

I apologize, it looks like the problem hasn't been fixed.

Something very strange happened to me. When I rebuilt after deleting the target directory and Cargo.lock, it seemed to be fixed, but when I set the dependency to a Git repository after the PR was merged, it didn't fix the problem. Setting the dependency to a local repository makes the problem go away, regardless of the patch.

I assumed this was caused by a bad local cache, so I cleared the extension and even reinstalled the entire rust compiler, but that didn't fix it.

Edit:
It seems that for some reason, rust-analyzer sometimes fails to load procedural macros properly from local repositories.

[Darksonn]

Okay, I reopened the issue. That said, I'm not sure we have to revert the change. It doesn't seem problematic.

[icedrocket]

I didn't see your comment before creating the revert PR.