[llvm] [docs] Add note about "Re-request review" (PR #104735)

[Fangrui Song via llvm-commits]

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@@ -125,6 +125,11 @@ commit message).
 If you suggest changes in a code review, but don't wish the suggestion to be
 interpreted this strongly, please state so explicitly.
 
+.. note::
+   After responding to reviewer comments,
+   press `Re-request review <https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/proposing-changes-to-your-work-with-pull-requests/requesting-a-pull-request-review#:~:text=After%20your%20pull%20request%20is%20reviewed>`_
+   to bring the Pull Request to the reviewer's attention.
----------------
MaskRay wrote:

`reviewers'` (there may be multiple reviewers)

https://github.com/llvm/llvm-project/pull/104735