[llvm] [Docs] Update documentation for the new GitHub workflow (PR #65162)

[Nicolai Hähnle via llvm-commits]

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@@ -122,28 +122,9 @@ For more information on LLVM's code-review process, please see :doc:`CodeReview`
 For developers to commit changes from Git
 -----------------------------------------
 
-Once a patch is reviewed, you should rebase it, re-test locally, and commit the
-changes to LLVM's main branch. This is done using `git push` if you have the
-required access rights. See `committing a change
-<Phabricator.html#committing-a-change>`_ for Phabricator based commits or
-`obtaining commit access <DeveloperPolicy.html#obtaining-commit-access>`_
-for commit access.
-
-Here is an example workflow using git. This workflow assumes you have an
-accepted commit on the branch named `branch-with-change`.
-
-.. code-block:: console
-
-  # Pull changes from the upstream main branch.
-  % git checkout main && git pull
-  # Rebase your change onto main.
-  % git rebase --onto main --root branch-with-change
-  # Rerun the appropriate tests if needed.
-  % ninja check-$whatever
-  # Check that the list of commits about to be pushed is correct.
-  % git log origin/main...HEAD --oneline
-  # Push to Github.
-  % git push origin HEAD:main
+Once a patch is reviewed, you can select the "Squash and merge" button in the
----------------
nhaehnle wrote:

I assume this means manual pushes are still acceptable, especially in the context of multi-commit sequences. That is probably worth stating explicitly somewhere.

https://github.com/llvm/llvm-project/pull/65162