Fix replacement order (backport #2300)

[mergify]

We need to replace the ...HEAD before adding the new [unreleased] link, otherwise the ...HEAD replacement finds two matches and fails.

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This is an automatic backport of pull request #2300 done by Mergify.

[mergify]

Cherry-pick of 55ee235 has failed:

On branch mergify/bp/release/2.1/pr-2300
Your branch is up to date with 'origin/release/2.1'.

You are currently cherry-picking commit 55ee235b.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   packages/vm/Cargo.toml

no changes added to commit (use "git add" and/or "git commit -a")

Cherry-pick of 38fea3a has failed:

On branch mergify/bp/release/2.1/pr-2300
Your branch is ahead of 'origin/release/2.1' by 1 commit.
  (use "git push" to publish your local commits)

You are currently cherry-picking commit 38fea3a7.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   packages/vm/Cargo.toml

no changes added to commit (use "git add" and/or "git commit -a")

Cherry-pick of 09f45bc has failed:

On branch mergify/bp/release/2.1/pr-2300
Your branch is ahead of 'origin/release/2.1' by 2 commits.
  (use "git push" to publish your local commits)

You are currently cherry-picking commit 09f45bc3.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	deleted by us:   .taplo.toml

no changes added to commit (use "git add" and/or "git commit -a")

Cherry-pick of 961abe6 has failed:

On branch mergify/bp/release/2.1/pr-2300
Your branch is ahead of 'origin/release/2.1' by 3 commits.
  (use "git push" to publish your local commits)

You are currently cherry-picking commit 961abe68.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   packages/vm/Cargo.toml

no changes added to commit (use "git add" and/or "git commit -a")

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally