Typos: @exportS3method -> @exportS3Method

[HenrikBengtsson]

TL;DR

There are several instances of @exportS3method that I think should be @exportS3Method. See PR #1590 for what I think needs to be fixed.

Background

✖ Future-class.R:862: S3 method `packages.Future` needs @export or @exportS3method tag.
✖ Future-class.R:855: S3 method `globals.Future` needs @export or @exportS3method tag.

Following these instructions, I then got:

✖ Future-class.R:854: @exportS3method is not a known tag.
✖ Future-class.R:861: @exportS3method is not a known tag.
✖ Future-class.R:862: S3 method `packages.Future` needs @export or @exportS3method tag.
✖ Future-class.R:855: S3 method `globals.Future` needs @export or @exportS3method tag.

[llrs]

There are several related issues to this: #1585 and #1587