Finalise Rustup Windows Arm64 support

[Alovchin91]

This PR finalises Windows Arm64 support by doing the following:

• Removes the workaround to exclude Ring on Windows Arm64. Ring 0.17.x fully supports it. Split-off into Re-enable Ring support on Windows Arm64 #3845
• Adds aarch64-pc-windows-msvc download link to cloud-invalidation.txt so that this script could pick it up.
  • Does the same for aarch64-apple-darwin because why not?
• Updates the Other Installation Methods page to include Windows Arm64 version of Rustup. Split-off into Add Windows Arm64 to Other Installation Methods #3854
• Updates the rustup.rs website to offer the arm64 version of Rustup on Windows Arm64.

The last part is the most "fragile" in my view because I don't know how the artefacts get published on rustup.rs, and detecting the arm64 CPU also required some async code that won't work in Firefox (but VS Code website’s arm64 detection doesn't work in Firefox either).

[djc]

(This largely looks good to me, modulo one nit: would be nice to rebase away the merge commit.)

[Alovchin91]

(would be nice to rebase away the merge commit.)

Done! I've been rebasing for years now so I didn't realise "Update fork" button would actually create a merge commit 😅

[rami3l]

(would be nice to rebase away the merge commit.)

Done! I've been rebasing for years now so I didn't realise "Update fork" button would actually create a merge commit 😅

@Alovchin91 You should've clicked "update with rebase". GitHub's default behavior is merging, unfortunately we cannot change it for now.

[rami3l]

LGTM! I'll ping t-infra again and let's see what we can do about https://win.rustup.rs/aarch64:
https://rust-lang.zulipchat.com/#narrow/stream/242791-t-infra/topic/.60win.2Erustup.2Ers.60.20should.20provide.20an.20.60aarch64.60.20installer

[Alovchin91]

@rami3l Do you think it would make sense to split everything except rustup.rs website part off to a new PR that could be merged without waiting for infra? 🤔 It might already be helpful to have proper links in Other Installation Methods + the PR pipeline.

[rami3l]

@rami3l Do you think it would make sense to split everything except rustup.rs website part off to a new PR that could be merged without waiting for infra? 🤔 It might already be helpful to have proper links in Other Installation Methods + the PR pipeline.

@Alovchin91 Yes, definitely. You can also use https://static.rust-lang.org/rustup/dist/aarch64-pc-windows-msvc/rustup-init.exe temporarily instead of https://win.rustup.rs/aarch64 first, then make a small PR to change that into the final URL. It's your call.

[Alovchin91]

@rami3l I think I'd prefer to keep it tidy and wait for the infra ☺️ Split off into #3854

[rami3l]

Status: Waiting for infra's deployment of https://win.rustup.rs/aarch64. I just tested and the link seems to work without issues! Thanks a lot, @jdno!

A note to @Alovchin91: for the actual changes being made here to be in effect, we might have to wait until the next official release of Rustup. The latest version of the docs, however, can be found here. Thank you for your patience :)