Deny 2018 idiom lints

[jyn514]

error: hidden lifetime parameters in types are deprecated
  --> library/stdarch/crates/std_detect/src/detect/os/linux/cpuinfo.rs:20:48
   |
20 |     pub(crate) fn field(&self, field: &str) -> CpuInfoField {
   |                                                ^^^^^^^^^^^^- help: indicate the anonymous lifetime: `<'_>`
   |
   = note: `-D elided-lifetimes-in-paths` implied by `-D warnings`

This lint is allow by default, which is why this wasn't spotted earlier.

cc rust-lang/rust#83776 (comment)

[rust-highfive]

r? @Amanieu

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[Amanieu]

Could you add #![deny(rust_2018_idioms)] at the crate root for all crates?

[jyn514]

Looks like CI is stuck?

[Amanieu]

It's stuck in rust-lang/rust too. Let's just wait it out.

[jyn514]

Yay, CI is finally passing :D