[llvm] workflows: Automatically make backport requests from merged PRs (PR #126993)

[Aiden Grossman via llvm-commits]

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@@ -460,6 +462,20 @@ If a commit you want to backport does not apply cleanly, you may resolve
 the conflicts locally and then create a pull request against the release
 branch.  Just make sure to add the release milestone to the pull request.
 
+
+Pull Requests
+^^^^^^^^^^^^^
+
+If you add the current Release Milestone to a pull request, then a backport
+request will be made automatically without the need to add any additional
+comments like you must do for issues.  You can even add the Milestone after
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boomanaiden154 wrote:

nit: `s/Milestrone/milestone`?

https://github.com/llvm/llvm-project/pull/126993