The unicorn/no_useless_spread rule has a bug causing arrays with multiple spread operators to be incorrectly fixed.

# expected result
[...[1,2,3], ...[4,5,6]]  -> [1,2,3,4,5,6]

# actual result
[...[1,2,3], ...[4,5,6]]  -> [1,2,3]

Here's a failing test for these cases:
e1ec854

Tried to fix this but I'm not proficient in Rust. Hopefully someone can take a look. Thanks!