fix hundreds of clippy warnings

[joseluis]

Single instances of: clippy::wrong_self_convention, clippy::enum_variant_names and clippy::vec_box are allowed, since the solutions albeit potentially simple are nevertheless non-straight forward.

[knickish]

@not-fl3 will have to weigh in on this one, historically has not liked some of the clippy conventions. Other than the change to the unsafe block (which should be in a separate PR in my opinion), I'm happy to merge it if he approves

[joseluis]

Fantastic. I don't mind changing something for a global preference. I considered it for needless_return but ended up rustifying them.

Both changes inside unsafe blocks are needless_borrow which indeed warns the semantics could change in unsafe blocks, but in this case on one side it passes miri and on the other if I understand it correctly &*expr de-rreferences expr then re-references it immediately, which is a no-op that doesn't seem to serve any extra purpose like coercing lifetimes... But I don't mind separating it if that's gonna be easier.

[knickish]

I still would prefer the unsafe one to be a separate PR. The change itself looks good though

[joseluis]

I've removed the unsafe-related changes and will do a different PR.

[knickish]

Thanks!