This adds support for `Rng::range(a..b)` and `Rng::range(a..=b)`,
replacing `Rng::range(a, b)`. `a` and `b` must now implement
`PartialEq`.
This is a breaking change. In most cases, replacing
`Rng::gen_range(a, b)` with `Rng::gen_range(a..b)` should be enough,
however type annotations may be necessary, and `a` and `b` can no longer
be references or SIMD types.
SIMD types are still supported by `UniformSampler::sample_single`.
Some clippy warnings were fixed as well.