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.

Inizia da core/src/main/java/org/apache/druid/timeline/VersionedIntervalTimeline.java e leggi findFullyOvershadowed(), in particolare i cicli intorno alle righe 364-404 e i commenti per completePartitionsTimeline e incompletePartitionsTimeline. Chiarisci perché il primo ciclo itera su entrambe le timelines, mentre il secondo itera solo su incompletePartitionsTimeline; i commenti dovrebbero rendere comprensibile questa distinzione.

Scritto dal modello di indicizzazione a partire dal testo della issue.