Diagnostics migr const eval
This PR should eventually contain all diagnostic migrations for the `rustc_const_eval` crate.
r? `@davidtwco`
`@rustbot` label +A-translation
Migrate `rustc_ty_utils` to `SessionDiagnostic`
I have migrated the `rustc_ty_utils` crate to use `SessionDiagnostic`, motivated by the [recent blog post about the diagnostic translation effort](https://blog.rust-lang.org/inside-rust/2022/08/16/diagnostic-effort.html).
This is my first PR to the Rust repository, so if I have missed anything, or anything needs to be changed, please let me know! 😄
`@rustbot` label +A-translation
Migrate ast lowering to session diagnostic
I migrated the whole rustc_ast_lowering crate to session diagnostic *except* the for the use of `span_fatal` at /compiler/rustc_ast_lowering/src/expr.rs#L1268 because `#[fatal(...)]` is not yet supported (see https://github.com/rust-lang/rust/pull/100694).
fluent: mandate slug names to be prefixed by crate name
This is currently only convention, but not actively checked for.
Additionally, improve error messages to highlight the path of the offending fluent file rather than the identifier preceding it.
This will conflict with #100671, so I'll leave it as draft until that's merged.
Migrate `rustc_plugin_impl` to `SessionDiagnostic`
Migration of the `rustc_plugin_impl` crate.
~Draft PR because it is blocked on #100694 for `#[fatal(...)]` support~ (this has been merged, and I've changed over to `#[diag(...)]` now too), but I would also like to know if what I did with `LoadPluginError` is okay, because all it does is display the error message from `libloading` ([See conversation on zulip](https://rust-lang.zulipchat.com/#narrow/stream/147480-t-compiler.2Fwg-diagnostics/topic/.23100717.20diagnostic.20translation/near/294327843)). This crate is apparently for a deprecated feature which is used by servo, so I don't know how much this matters anyway.
Convert diagnostics in parser/expr to SessionDiagnostic
This migrates all the easy cases in `rustc_parse::parser::expr` to `SessionDiagnostic`s, I've left things such as `multipart_suggestion`s out for now in the hopes of a derive API being developed soon.
Migrate rustc_ast_passes diagnostics to `SessionDiagnostic` and translatable messages (first part)
Doing a full migration of the `rustc_ast_passes` crate.
Making a draft here since there's not yet a tracking issue for the migrations going on.
`@rustbot` label +A-translation
