Clarifying VersionedIntervalTimeline.findFullyOvershadowed()

In #7547, @jihoonson added clarifying comments for `completePartitionsTimeline` and `incompletePartitionsTimeline` fields in `VersionedIntervalTimeline`. One of the comments say that "IncompletePartitionsTimeline also includes completePartitionsTimeline".

It explains to me why the second part of the `findFullyOvershadowed()` algorithm iterates only over `incompletePartitionsTimeline`:

https://github.com/apache/incubator-druid/blob/7b9bd5359db80bdd9bb3f547161f94b369469b76/core/src/main/java/org/apache/druid/timeline/VersionedIntervalTimeline.java#L392-L404

But it doesn't explain why then the first part does exactly the same loop over both `completePartitionsTimeline` and `incompletePartitionsTimeline`:

https://github.com/apache/incubator-druid/blob/7b9bd5359db80bdd9bb3f547161f94b369469b76/core/src/main/java/org/apache/druid/timeline/VersionedIntervalTimeline.java#L364-L382

Related to #7433 and #8070.

Commencez dans core/src/main/java/org/apache/druid/timeline/VersionedIntervalTimeline.java et lisez findFullyOvershadowed(), en particulier les boucles autour des lignes 364-404 ainsi que les commentaires de completePartitionsTimeline et incompletePartitionsTimeline. Clarifiez pourquoi la première boucle itère sur les deux timelines, tandis que la seconde itère uniquement sur incompletePartitionsTimeline ; les commentaires devraient rendre cette distinction compréhensible.

Rédigé par le modèle d'indexation à partir du texte de l'issue.