Rollup merge of #131710 - ShE3py:parse_format_apostrophes, r=compiler-errors

Remove `'apostrophes'` from `rustc_parse_format`

The rest of the compiler uses \`grave accents\`, while `rustc_parse_format` uses \`'apostrophes.'\`

Also makes the crate compile as a stand-alone:
```
~/rust/compiler/rustc_parse_format $ cargo check
   Compiling rustc_index_macros v0.0.0 (/home/lieselotte/rust/compiler/rustc_index_macros)
error[E0277]: `syn::Lit` doesn't implement `Debug`
  --> compiler/rustc_index_macros/src/newtype.rs:52:57
   |
52 |                         panic!("Specified multiple max: {old:?}");
   |                                                         ^^^^^^^ `syn::Lit` cannot be formatted using `{:?}` because it doesn't implement `Debug`
   |
   = help: the trait `Debug` is not implemented for `syn::Lit`
   = note: this error originates in the macro `$crate::const_format_args` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)

error[E0277]: `syn::Lit` doesn't implement `Debug`
  --> compiler/rustc_index_macros/src/newtype.rs:64:74
   |
64 |                         panic!("Specified multiple debug format options: {old:?}");
   |                                                                          ^^^^^^^ `syn::Lit` cannot be formatted using `{:?}` because it doesn't implement `Debug`
   |
   = help: the trait `Debug` is not implemented for `syn::Lit`
   = note: this error originates in the macro `$crate::const_format_args` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)

For more information about this error, try `rustc --explain E0277`.
error: could not compile `rustc_index_macros` (lib) due to 2 previous errors
```
`@rustbot` label +A-diagnostics

1 files changed, 4 insertions, 4 deletions

diff --git a/compiler/rustc_parse_format/src/lib.rs b/compiler/rustc_parse_format/src/lib.rs
index e7ef4385baf..1716f417969 100644
--- a/compiler/rustc_parse_format/src/lib.rs
+++ b/compiler/rustc_parse_format/src/lib.rs
@@ -473,19 +473,19 @@ impl<'a> Parser<'a> {
             }
 
             pos = peek_pos;
-            description = format!("expected `'}}'`, found `{maybe:?}`");
+            description = format!("expected `}}`, found `{}`", maybe.escape_debug());
         } else {
-            description = "expected `'}'` but string was terminated".to_owned();
+            description = "expected `}` but string was terminated".to_owned();
             // point at closing `"`
             pos = self.input.len() - if self.append_newline { 1 } else { 0 };
         }
 
         let pos = self.to_span_index(pos);
 
-        let label = "expected `'}'`".to_owned();
+        let label = "expected `}`".to_owned();
         let (note, secondary_label) = if arg.format.fill == Some('}') {
             (
-                Some("the character `'}'` is interpreted as a fill character because of the `:` that precedes it".to_owned()),
+                Some("the character `}` is interpreted as a fill character because of the `:` that precedes it".to_owned()),
                 arg.format.fill_span.map(|sp| ("this is not interpreted as a formatting closing brace".to_owned(), sp)),
             )
         } else {