`rust-src` component not found.

Created by: ntduan

When I execute cargo +nightly Contract build, I got an error.

 `rust-src` component not found. Run `rustup component add rust-src`.

But I think I have rust-src installed, and the rustup component list | grep rust-src also shows that I have rust-src installed.

I tried to specify rust-src manually through export XARGO_RUST_SRC=/home/nzzt/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library, and I succeeded in the next step, but unfortunately another error occurred.

I checked the directory on my computer and found that it didn't match the actual directory.