Remove the diagnostic lints

[JonathanBrouwer]

Removes the untranslatable_diagnostic and diagnostic_outside_of_impl lints
These lints are allowed for a while already. Per rust-lang/compiler-team#959, we no longer want to enforce struct diagnostics for all usecases, so this is no longer useful.

r? @Kivooeo
I recommend reviewing commit by commit (also feel free to wait with reviewing until the MCP is accepted)

@rustbot +S-blocked
Blocked by rust-lang/compiler-team#959

[rustbot]

Some changes occurred to MIR optimizations

cc @rust-lang/wg-mir-opt

rust-analyzer is developed in its own repository. If possible, consider making this change to rust-lang/rust-analyzer instead.

cc @rust-lang/rust-analyzer

The Miri subtree was changed

cc @rust-lang/miri

Some changes occurred in compiler/rustc_attr_parsing

cc @jdonszelmann

Some changes occurred in compiler/rustc_hir/src/attrs

cc @jdonszelmann

Some changes occurred in compiler/rustc_passes/src/check_attr.rs

cc @jdonszelmann

Some changes occurred to constck

cc @fee1-dead

Some changes occurred to the CTFE / Miri interpreter

cc @rust-lang/miri

Some changes occurred to the CTFE machinery

cc @RalfJung, @oli-obk, @lcnr

Some changes occurred in src/tools/clippy

cc @rust-lang/clippy

Some changes occurred in src/tools/rustfmt

cc @rust-lang/rustfmt

Some changes occurred in exhaustiveness checking

cc @Nadrieril

Some changes occurred in compiler/rustc_codegen_cranelift

cc @bjorn3

[bjorn3]

As a nice side effect this will make patching rustc to support bootstrapping from rustc 1.83 and below a tiny bit easier. #[rustc_lint_diagnostics] was only introduced in rustc 1.84.

[rust-bors]

☔ The latest upstream changes (presumably #150957) made this pull request unmergeable. Please resolve the merge conflicts.