gh-38757: fix the output of method `acyclic_orientations`
This PR fixes the issue with the output of method `acyclic_orientations`
reported in https://ask.sagemath.org/question/79427/the-acyclic-
orientations-function-behaves-unexpectedly/.
Now the method outputs digraphs with the correct orientation of the
arcs.
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### :hourglass: Dependencies
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URL: https://github.com/sagemath/sage/pull/38757
Reported by: David Coudert
Reviewer(s): Dima Pasechnik
