no_std vest-dsl

[Furao]

When generating a parser with vest-dsl and building it for a no_std environment, I get an issue with Vecs. I found I needed to add the following to the generated file:

use alloc::vec::Vec;

On a side note, I was wondering if you had considered using statically sized Vecs, such as the implementation in the heapless library so a user doesn't need to bring their own allocator in a no_std environment? I am not sure about all the ramifications of that approach, especially to the verification story, but it could improve user experience as the user would just need to make sure they have a large enough stack for the Vecs.