Clarify that ::foo paths are not necessarily based off of the "crate root"

[Manishearth]

Part of rust-lang/rust#82876

[CryZe]

Suggested change

	> Beginning with the 2018 Edition, paths starting with `::` resolve from from
	> Beginning with the 2018 Edition, paths starting with `::` resolve from

[Havvy]

Also, I think the default is to describe the currentmost edition's behavior outside of the edition differences section and specify how it's different in older in the edition differences section. So the part that is in the "Beginning with the 2018 edition" should be the description of what a global path is.

[ehuss]

I think the default is to describe the currentmost edition's behavior outside of the edition differences section

I don't think this issue has been settled (see #698). The original intent was to have the main text describe what is common in both editions, and to use sidebars to explain where it diverges (with exceptions like the async chapters). I'm starting to lean a little more towards preferring the "describe latest edition" approach, but there are some places where it can be a little awkward.

Maybe @Manishearth has an opinion on which approach seems better overall?

(BTW, thanks for the PR, I kinda made a mess on this section.)

[Manishearth]

When I wrote this PR I thought about it and decided not to because it was the reference, but I don't mind doing it. I did find it easier to describe what it was (a "global path") and then describe edition differences in a clear mirrored fashion.

[Havvy]

💟 Thanks!

I still prefer the idea of documenting the current edition as primary, but that can be redecided on elsewhere. The whole await/async thing might actually be in a better spot if k#keywords become a thing.