Display help message when fluent arg was referenced incorrectly
The fluent argument syntax is a little special and easy to get wrong, so we emit a small help message when someone gets it wrong.
Example:
```
parser_mismatched_closing_delimiter = mismatched closing delimiter: `${delimiter}`
```
panics with
```
thread 'rustc' panicked at 'Encountered errors while formatting message for `parser_mismatched_closing_delimiter`
help: Argument `delimiter` exists but was not referenced correctly. Try using `{$delimiter}` instead
attr: `None`
args: `FluentArgs([("delimiter", String("}"))])`
errors: `[ResolverError(Reference(Message { id: "delimiter", attribute: None }))]`', compiler/rustc_errors/src/translation.rs:123:21
```
fixes#103539
The fluent argument syntax is a little special and easy to get wrong, so
we emit a small help message when someone gets it wrong.
Example:
```
parser_mismatched_closing_delimiter = mismatched closing delimiter: `${delimiter}`
```
panics with
```
thread 'rustc' panicked at 'Encountered errors while formatting message for `parser_mismatched_closing_delimiter`
help: Argument `delimiter` exists but was not referenced correctly. Try using `{$delimiter}` instead
attr: `None`
args: `FluentArgs([("delimiter", String("}"))])`
errors: `[ResolverError(Reference(Message { id: "delimiter", attribute: None }))]`', compiler/rustc_errors/src/translation.rs:123:21
```
Port `dead_code` lints to be translatable.
This adds an additional comma to lists with three or more items, to be consistent with list formatters like `icu4x`.
r? `@davidtwco`
Rewrite implementation of `#[alloc_error_handler]`
The new implementation doesn't use weak lang items and instead changes `#[alloc_error_handler]` to an attribute macro just like `#[global_allocator]`.
The attribute will generate the `__rg_oom` function which is called by the compiler-generated `__rust_alloc_error_handler`. If no `__rg_oom` function is defined in any crate then the compiler shim will call `__rdl_oom` in the alloc crate which will simply panic.
This also fixes link errors with `-C link-dead-code` with `default_alloc_error_handler`: `__rg_oom` was previously defined in the alloc crate and would attempt to reference the `oom` lang item, even if it didn't exist. This worked as long as `__rg_oom` was excluded from linking since it was not called.
This is a prerequisite for the stabilization of `default_alloc_error_handler` (#102318).
