Use itertools

[marxin]

In the future, we might want to use the following function: rust-itertools/itertools#934.

[davidlattimore]

I generally try to avoid putting partially inferred types (e.g. Vec<_>) on variables, since then rust-analyzer doesn't show the full type inline. e.g. in here we can see that files is a Vec<FileLayout<'data>>

But with a partial type, we can't:

Not a massive problem, but that's why I tend to use the turbofish perhaps more than some other people. I'm not strongly opposed to doing it with partially inferred types if you really want to though - I can still get the inferred type if I hover, it's just not always there like it is for a fully inferred type.

[marxin]

Sure, I fully understand your point. I've removed all the try_collect calls from the PR.