Less overzealous inlining

[Shnatsel]

Using vectorize() as opposed to directly calling functions annotated #[inline(always)] is meant to introduce an inlining barrier and make the compiler make inlining decisions. Therefore putting #[inline] on it is rather pointless: if I wanted aggressive inlining, I wouldn't be calling vectorize() in the first place.

#[inline] also enables cross-crate inlining, but since vectorize() is a generic function it will be instantiated in the caller crate, so this is not a concern.

More info about inlining: https://matklad.github.io/2021/07/09/inline-in-rust.html

Motivation

I'm seeing a large performance regression from switching from wide to fearless_simd in QuState/PhastFT#58 due to overly aggressive inlining. This alone doesn't fix it, but seems like a sensible first step.