platform-support: x86_64-linux-kernel should be *

[geofft]

The tier 3 platform x86_64-linux-kernel has support for core + alloc, and we test it in CI at https://github.com/fishinabarrel/linux-kernel-module-rust, so I think it should be marked **.

[XAMPPRocky]

Thank you for your issue! We just moved the platform support table to the rustc book, so I'm going to transfer this issue to rust-lang/rust.

[scrabsha]

Hi,
I'm Sasha, I've never contributed to Rust before, and I'd like to know if I can work on this issue.

If I understand correctly, this issue is just about fixing the Tier 3 table in the platform support file. Is that correct? Are there some other details that should be discussed before?

Edit: fixed link.

[geofft]

That sounds right to me, @scileo. Welcome!

Thanks for moving, @XAMPPRocky, apparently I checked right before it was moved :)