Dot production is not acting as a distance

[generall]

This line assumes, that dot function returns a simple dot production and negates it to make it work like a distance (smaller = closer)

hora/src/core/metrics.rs

Line 56 in a6759f8

dot(vec1, vec2).map(|x| -x)

But in reality, dot function is already negated in the SIMDOptmized inplementation:

hora/src/core/simd_metrics.rs

Line 32 in ce10e42

Ok(-(a.iter().zip(b).map(|(p, q)| p * q).sum::<$type_id>()))

Which leads to double inverting and incorrect use of Dot Production

[RXminuS]

I think this is even causing a panic when using CosineSimilarity (I'm getting an calling Option::unwrap() on a None value) which might be related to #17 ?