Rust-src not included in the standalone installer

[HydrogenC]

Describe the problem you are trying to solve

I am trying to configure a rust development environment on an offline machine.

Describe the solution you'd like

The auto-completion of editors and ides require the rust-src to work properly. Please include it in the standalone offline installer.

Notes

[kinnison]

@rust-lang/infra I think this belongs on rust-lang/rust since the standalone installers are built from there.

[dclong]

I'm encountering the same issue.

[SilvanCodes]

+1