Rollup merge of #140175 - Kivooeo:new-fix-one, r=compiler-errors

`rc""` more clear error message

here is small fix that provides better error message when user is trying to use `rc""` the same way it was made for `rb""`

example of it's work

```rust
  |
2 |     rc"\n";
  |     ^^ unknown prefix
  |
  = note: prefixed identifiers and literals are reserved since Rust 2021
help: use `cr` for a raw C-string
  |
2 -     rc"\n";
2 +     cr"\n";
  |
```

**related issue**
fixes #140170

cc `@cyrgani` (issue author)

1 files changed, 7 insertions, 0 deletions

diff --git a/compiler/rustc_parse/src/errors.rs b/compiler/rustc_parse/src/errors.rs
index 44b4e1a3e47..35cf4c1b00d 100644
--- a/compiler/rustc_parse/src/errors.rs
+++ b/compiler/rustc_parse/src/errors.rs
@@ -2141,6 +2141,13 @@ pub(crate) enum UnknownPrefixSugg {
     )]
     UseBr(#[primary_span] Span),
     #[suggestion(
+        parse_suggestion_cr,
+        code = "cr",
+        applicability = "maybe-incorrect",
+        style = "verbose"
+    )]
+    UseCr(#[primary_span] Span),
+    #[suggestion(
         parse_suggestion_whitespace,
         code = " ",
         applicability = "maybe-incorrect",