Clarify GITHUB_SHA for push event (github#34436)

Co-authored-by: Alex Nguyen <150945400+nguyenalex836@users.noreply.github.com>

content/actions/writing-workflows/choosing-when-your-workflow-runs/events-that-trigger-workflows.md

@@ -929,7 +929,7 @@ jobs:
 
 | Webhook event payload | Activity types | `GITHUB_SHA` | `GITHUB_REF` |
 | --------------------- | -------------- | ------------ | -------------|
-| [`push`](/webhooks-and-events/webhooks/webhook-events-and-payloads#push) | Not applicable | When you delete a branch, the SHA in the workflow run (and its associated refs) reverts to the default branch of the repository. | Updated ref |
+| [`push`](/webhooks-and-events/webhooks/webhook-events-and-payloads#push) | Not applicable | Tip commit pushed to the ref. When you delete a branch, the SHA in the workflow run (and its associated refs) reverts to the default branch of the repository. | Updated ref |
 
 {% note %}