Introduce a [workspace.dependencies] section in the top-level Cargo.toml

[nnethercote]

It lets us avoid a lot of repetition of crate versions, etc.

I've just done a few as a start. Many more can be done in follow-ups.

r? @Kobzol

[rustbot]

Some changes occurred in src/tools/rustfmt

cc @rust-lang/rustfmt

rustc_error_messages was changed

cc @davidtwco, @compiler-errors, @TaKO8Ki

This PR changes rustc_public

cc @oli-obk, @celinval, @ouz-a

Some changes occurred in compiler/rustc_attr_parsing

cc @jdonszelmann

Some changes occurred in compiler/rustc_codegen_ssa

cc @WaffleLapkin

Some changes occurred in exhaustiveness checking

cc @Nadrieril

Some changes occurred in src/tools/clippy

cc @rust-lang/clippy

The Miri subtree was changed

cc @rust-lang/miri

Some changes occurred in src/tools/compiletest

cc @jieyouxu

Some changes occurred in compiler/rustc_sanitizers

cc @rcvalle

[rustbot]

This PR was rebased onto a different master commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

[samueltardieu]

How would that work in the standalone Clippy repository?

[nnethercote]

Hmm, it won't. Likewise for other parts done in separate repositories: rustfmt, miri, anything else. That's annoying :/

[practicalrs]

Any particular reason why choosing
bitflags.workspace = true
syntax over
bitflags = { workspace = true }
?

[tshepang]

not author, but it hurts me eyes less... do you prefer the other form

[practicalrs]

bitflags = { } syntax is used a lot for other things. For me it's more consistent :)

[nnethercote]

It's shorter, that's all.