templates/rebase: mention the final stable N-1 release

Reflects reality, as described in
https://github.com/coreos/fedora-coreos-tracker/blob/main/Design.md#major-fedora-version-rebases

.github/ISSUE_TEMPLATE/rebase.md

@@ -78,8 +78,9 @@ If the packages in `next-devel` don't exactly match the last `next` release that
 
 - [ ] Ensure final `next` release has GA content
 
-### Build rebased `testing`
+### Build rebased `testing` and final `stable` release on N-1 
 
+- [ ] Build `stable`; promote it from the `testing` branch, which should still be on N-1. Don't release it yet (i.e. don't run the `release` job).
 - [ ] Build `testing`; promote it from the `next` branch instead of `testing-devel`. Don't release it yet (i.e. don't run the `release` job).
 
 ### Update [fedora-coreos-config](https://github.com/coreos/fedora-coreos-config/) `testing-devel`
@@ -95,9 +96,9 @@ If the packages in `next-devel` don't exactly match the last `next` release that
 
 Do these steps on GA day.
 
-### Release rebased `testing`
+### Release rebased `testing` and final `stable` release on N-1
 
-- [ ] Run the `release` job and start rollout.
+- [ ] Run the `release` job for the staged `testing` and `stable` builds and start rollout.
 - [ ] Set a new update barrier for the final release of N-1 on `testing`. In the barrier entry set a link to [the docs](https://docs.fedoraproject.org/en-US/fedora-coreos/update-barrier-signing-keys/). See [discussion](https://github.com/coreos/fedora-coreos-tracker/issues/480#issuecomment-1247314065)
 
 ### Disable `next-devel` stream if not needed

Design.md

@@ -87,6 +87,7 @@ The release process integrates with Fedora's release milestones in the following
         - Week -1 (Fedora "Go" Decision): `next` release:
           - `next` release with final Fedora GA content
         - Week 0 (GA release): triple release:
+          - `stable` release promoted from previous `testing` (on N-1)
           - `testing` release promoted from previous `next`
           - `next` release contains latest Fedora N content, including Bodhi updates
         - Week 2: triple release: