System Labeling docs should include an example

[ItsDoot]

How can Bevy's documentation be improved?

https://docs.rs/bevy/0.8.0/bevy/ecs/system/index.html#system-ordering

This section mentions system labeling, but doesn't explain how the methods it provides should be used. And if an example exists elsewhere in the docs, it should link to there.

[Gingeh]

Would adding a link to this example be sufficient?