Improve the Rosetta installation hint (backport #13378)

[mergify]

Motivation

The Nix daemon detects supported system types at start time, so it needs to be restarted to detect x86_64-darwin support.

Context

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This is an automatic backport of pull request #13378 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of 20ba6be has failed:

On branch mergify/bp/2.29-maintenance/pr-13378
Your branch is up to date with 'origin/2.29-maintenance'.

You are currently cherry-picking commit 20ba6be74.
  (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:   src/libstore/unix/build/derivation-builder.cc

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