Remove () as a valid bundle

[alice-i-cecile]

From #2522, the 0-element-tuple creates a bundle currently. This is always user error in some form, and should be caught at compile time.

To change this, modify the 0 in this line to a 1:

bevy/crates/bevy_ecs/src/bundle.rs

Line 96 in 86cc70b

all_tuples!(tuple_impl, 0, 15, C);

[james7132]

all_tuples currently has a bug where it errors out when the start is anything other than 0. This was caught and fixed as a part of #2381, but that hasn't been merged yet.

I can split that out if need be.

[alice-i-cecile]

Closing this as I found a good use of the empty tuple bundle! When combined with spawn_batch it can be used to quickly make large numbers of empty entities. If nothing else, that's useful for benchmarking.