[release-branch.go1.24] runtime: document that cleanups can run concurrently with each other
For #71825.
Fixes #71955.
Change-Id: I25af19eb72d75f13cf661fc47ee5717782785326
Reviewed-on: https://go-review.googlesource.com/c/go/+/652637 Reviewed-by: Keith Randall <khr@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Michael Knyszek <mknyszek@google.com> Reviewed-by: Keith Randall <khr@google.com>