ci: correct the companion-workflow comments

The ci-docs-only header claimed the ruleset already requires "Quick Checks";
it does not, and this PR deliberately leaves it that way. Say what is true
today and why the job is mirrored ahead of the ruleset change.

Also move the byte-identical requirement onto ci.yml's quick-checks job, which
is the more likely edit site, instead of pointing at a comment that was not
there.

.github/workflows/ci-docs-only.yml

@@ -12,20 +12,24 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-# Companion to ci.yml for the required "Test and Lint" and "Quick Checks"
+# Companion to ci.yml for required status checks.
-# status checks.
 #
-# ci.yml skips docs-only pull requests via paths-ignore, but the branch
+# ci.yml skips docs-only pull requests via paths-ignore, but the branch ruleset
-# ruleset requires checks named "Test and Lint" and "Quick Checks" — without
+# requires a check named "Test and Lint" — without this workflow a docs-only PR
-# this workflow a docs-only PR would wait on those checks forever. This
+# would wait on it forever. This workflow triggers on exactly the paths ci.yml
-# workflow triggers on exactly the paths ci.yml ignores and reports success
+# ignores and reports success under the same job name. Mixed PRs trigger both
-# under the same job names. Mixed PRs trigger both workflows and the real
+# workflows and the real check still gates: a required check with any failing
-# checks still gate: a required check with any failing run blocks the merge.
+# run blocks the merge.
 # https://docs.github.com/en/repositories/configuring-branches-and-merges-in-your-repository/defining-the-mergeability-of-pull-requests/troubleshooting-required-status-checks#handling-skipped-but-required-checks
 #
+# "Quick Checks" is mirrored here ahead of the ruleset change that will make it
+# required too (rustfs/backlog#1599). It is not required yet, so today this job
+# is inert; adding it first is what lets that ruleset change land without
+# stranding docs-only PRs on a check nobody reports.
+#
 # Keep the paths list below in sync with the pull_request paths-ignore list
 # in ci.yml, and keep the quick-checks steps below byte-identical to the
-# quick-checks job in ci.yml (see the comment on that job).
+# quick-checks job in ci.yml.
 
 name: Continuous Integration (docs only)
 

.github/workflows/ci.yml

@@ -96,6 +96,10 @@ jobs:
 
   # Fast, compile-free checks that fail early so contributors get feedback in
   # ~1 minute instead of waiting for the full test job.
+  #
+  # These steps are mirrored byte-for-byte in ci-docs-only.yml so that a mixed
+  # PR, which reports two check runs named "Quick Checks", cannot get one red
+  # and one green. Edit both jobs together.
   quick-checks:
     name: Quick Checks
     if: github.event_name != 'pull_request' || github.event.action != 'closed'