v6.0.0

Migration: FloatPointCompatible now uses an associated scalar type

FloatPointCompatible no longer takes the scalar as a generic parameter. Implementations should define type Scalar instead.

Before:

impl FloatPointCompatible<f32> for MyPoint {
    fn from_xy(x: f32, y: f32) -> Self { ... }
    fn x(&self) -> f32 { ... }
    fn y(&self) -> f32 { ... }
}

After:

impl FloatPointCompatible for MyPoint {
    type Scalar = f32;

    fn from_xy(x: f32, y: f32) -> Self { ... }
    fn x(&self) -> f32 { ... }
    fn y(&self) -> f32 { ... }
}

Public float overlay APIs were simplified accordingly. Types that previously carried both point and scalar generics now generally use only the point type, with scalar values expressed as P::Scalar.