Rustdoc example for Ref

[stepancheg]

No description provided.

[rlidwka]

If you compare two things (even for the sake of the example), the difference between them usually deserves a mention.

Are those exactly equivalent, or are there performance implications for doing filtering inside the system? Would you ever want to write Query<Ref<MyComponent>, Changed<MyComponent>>?

Also, first query fetches Entity and second doesn't, not sure if that's relevant. Maybe adding Entity to second query or removing it from the first will create less confusion if people start copy-pasting things.

[stepancheg]

@rlidwka

Are those exactly equivalent, or are there performance implications for doing filtering inside the system?

I would appreciate if you suggest better wording, or just submit a better PR with better explanations.

[stepancheg]

Removed entity from first example.