Auto merge of #54057 - matthiaskrgr:stabilize-edition-plus-clippy, r=Mark-Simulacrum

Stabilize edition 2018; also updates Clippy, RLS and Cargo

Supersedes https://github.com/rust-lang/rust/pull/53999 , https://github.com/rust-lang/rust/pull/53935
Clippy build was failing there because crate_visibility_modifier feature was taken out of edition 2018 and clippy used it.
The clippy update enables the corresponding feature explicitly.

r? @Mark-Simulacrum