Correct usage of `ComputeTaskPool` is unclear

## How can Bevy's documentation be improved?

I used [`ComputeTaskPool`](https://docs.rs/bevy/latest/bevy/tasks/prelude/struct.ComputeTaskPool.html) to queue several computationally heavy tasks that I wanted to run in the background, but complete by the next frame:
https://github.com/Crusaders-of-Rust/cormine/blob/b0d0a65207695e3c8b6266de71da4d80f706bb12/src/main.rs#L246-L320

However, checking frame counts, it seems to take up to 18 frames for the sync tasks to be ready. It's not clear from these docs how exactly this pool should be used to queue tasks for completion by the next frame.

Start with the ComputeTaskPool documentation on docs.rs and the linked example in src/main.rs around lines 246-320. Trace how the computational tasks are queued and synchronized, then clarify in the documentation how to use the pool when tasks are expected to complete by the next frame and explain the observed delay.

Written by the indexing model from the issue text.