Changelog:

• Security and unsafe: Policy change, remove fork-protection, use zerocopy to replace some unsafe code.
• Dependencies: Bump MSRV to 1.63.0, update to rand_core v0.9.0.
• Features: Support std feature without getrandom or rand_chacha, enable small_rng by default, rename features, etc.
• API changes: rand_core traits: Add various functions and traits, rename some methods and associated types.
• API changes: Rng trait and top-level fns: Rename and modify some top-level functions and traits.
• API changes: RNGs: Fix seed size, remove parameters.
• API changes: Sequences: Split trait SliceRandom, add new methods.
• API changes: Distributions: renames: Rename modules, distributions, and traits.
• API changes: Distributions: Relax bounds, remove impls, add new functions and distributions.
• API changes: Weighted distributions: Add modules, traits, and functions.
• API changes: SIMD: Switch to std::simd, expand SIMD & docs.
• Reproducibility-breaking changes: Make ReseedingRng::reseed discard remaining data, change SmallRng::seed_from_u64 implementation, etc.
• Reproducibility-breaking optimisations: Optimize some functions and algorithms.
• Other optimisations: Improve SmallRng initialization performance, optimize SIMD widening multiply.
• Other: Add Cargo.lock.msrv file, reformat with rustfmt, apply Clippy suggestions, move benchmarks to new benches crate and migrate to Criterion.
• Documentation: Improve ThreadRng related docs, enable experimental feature, better doc of crate features.