`rc""` instead of `cr""` should get a clear diagnostic

[cyrgani]

Code

fn main() {
    rc"\n";
}

Current output

error: prefix `rc` is unknown
 --> src/lib.rs:2:5
  |
2 |     rc"\n";
  |     ^^ unknown prefix
  |
  = note: prefixed identifiers and literals are reserved since Rust 2021
help: consider inserting whitespace here
  |
2 |     rc "\n";
  |       +

error: expected one of `!`, `.`, `::`, `;`, `?`, `{`, `}`, or an operator, found `"\n"`
 --> src/lib.rs:2:7
  |
2 |     rc"\n";
  |       ^^^^ expected one of 8 possible tokens

Desired output

error: prefix `rc` is unknown
help: consider using `cr` instead:

Rationale and extra context

not sure whether the combination of c-string and raw string is common, but this seems like a plausible mistake if it is

Other cases

Rust Version

rustc 1.88.0-nightly (d6c1e454a 2025-04-21)
binary: rustc
commit-hash: d6c1e454aa8af5e7e59fbf5c4e7d3128d2f99582
commit-date: 2025-04-21
host: x86_64-unknown-linux-gnu
release: 1.88.0-nightly
LLVM version: 20.1.2

Anything else?

No response

[Kivooeo]

@rustbot claim