SIMD on AArch64 is now available on stable Rust

[Shnatsel]

The README states:

Skia also supports ARM NEON instructions, which are unavailable in a stable Rust at the moment. Therefore a fallback scalar implementation will be used instead on ARM and other non-x86 targets. So if you're targeting ARM, you better stick with Skia.

However, Rust now supports AArch64 SIMD intrinsics on stable starting with v1.59; see rust-lang/stdarch#1266 for details.

Note that documentation still displays the intrinsics as unstable due to a rustdoc bug: rust-lang/stdarch#1268

[CryZe]

Yeah I have an open PR for it: #39

I'll try to pick it up again.

[Shnatsel]

Oh, and I see you've been working on adding it to safe_arch and bytemuck as well! Amazing! Thank you so much!

[yisibl]

@CryZe Thank you for your efforts. Looking forward to the completion of PR #39.