Directly build an owned `Finder`

[marmeladema]

Hi :)

I have a use case where I already have an owned needle in the form of Vec<u8> / Box<[u8]> and we would like to build an owned Finder.
As far as I aware, the way to go is to:

let finder = Finder:new(&bytes).into_owned();

but this will pass the bytes by reference, just to heap allocate them again in the into_owned() call.
Is there a way to directly build an owned Finder without requiring an additional heap allocation and drop? I am very sorry if I have missed it!
The code in question is very performance sensitive and we would like to avoid paying any extra cost that we think could be avoided.

If you think this is something that this crate could offer, I am happy to work on the implementation.

Thank you in advance!

[BurntSushi]

I think this is probably fine to support. The annoying thing is that the builder already has build_forward, build_reverse and build_forward_with_ranker. Adding another way to build it that accepts Into<Vec<u8>> means that we need another 3 routines. Pretty annoying, but I don't really see another way?

I'd also be fine with a impl From<Vec<u8>> for Finder and impl From<String> for Finder conveniences as well.