[stdlib] NFC: Restore doc comment for Unsafe[Mutable]BufferPointer

[krilnon]

Moves a // comment up above a /// documentation comment, since the latter needs to be attached directly to the declaration or it won't be picked up as documentation.

[krilnon]

@swift-ci please smoke test

[benrimmington]

I think the comment should just be removed. Library Evolution in Swift:

Adding or removing the @frozen attribute on a struct or enum is not allowed.

(Likewise, all the FIXME(ABI) comments?)

[krilnon]

I’m fine with that approach too, Ben. My goal here is just to bring the documentation back; hopefully someone more familiar with the status of the FIXME can comment on whether it’s best to move or remove the comment.

Edit: Updated the PR for that approach; can revert if someone wants to keep the comment.

[glessard]

I agree that we can remove this FIXME. ABI stability makes the change suggested here untenable, therefore removing it is the right thing to do.

[glessard]

@swift-ci please smoke test and merge

[krilnon]

@swift-ci please smoke test and merge

[glessard]

@krilnon Could you also make a PR with this change cherry-picked to the release/5.8 branch? It seems a worthwhile change to include from the documentation angle. We'll see if a branch manager agrees.

[krilnon]

@glessard Made one in #63362; let me know if anything looks off about the structure/reviewers, etc. Haven't done the release cherry-pick thing before.

[glessard]

LGTM – thanks