.github: document where runs/output can be examined

Signed-off-by: Patrick Donnelly <[email protected]>

Author: batrick

.github/workflows/create-backport-trackers.yml

@@ -2,6 +2,7 @@
 name: Create backport trackers for trackers in "Pending Backport" state
 on:
   # To manually trigger this: https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows#workflow_dispatch
+  # View past runs and output: https://github.com/ceph/ceph/actions/workflows/create-backport-trackers.yml
   workflow_dispatch:
     inputs:
       issues: