ES-SlicingAlgorithm: modify rule 4 to account for PPDG
The PPDG makes some transitive CDs direct, in order to remove some of them. The ES-SDG then stops some of these, which had the consequence of not reaching `Enter` in some cases.
The PPDG makes some transitive CDs direct, in order to remove some of them. The ES-SDG then stops some of these, which had the consequence of not reaching `Enter` in some cases.