When we add an alternate remote, we should fetch that remote to prime it's usage.
<rdar://problem/92733391>
Pull request: https://github.com/apple/WebKit/pull/5
Pull request: https://github.com/WebKit/WebKit/pull/498
Committed r293831 (250304@main): <https://commits.webkit.org/250304@main> Reviewed commits have been landed. Closing PR #498 and removing active labels.