Fix trait object error code

compiler/rustc_typeck/src/check/fn_ctxt/_impl.rs

@@ -952,7 +952,7 @@ fn maybe_lint_bare_trait(&self, qpath: &QPath<'_>, hir_id: hir::HirId, span: Spa
                     let mut err = rustc_errors::struct_span_err!(
                         self.sess(),
                         self_ty.span,
-                        E0783,
+                        E0782,
                         "{}",
                         msg,
                     );

src/test/ui/editions/dyn-trait-sugg-2021.stderr

@@ -1,4 +1,4 @@
-error[E0783]: trait objects without an explicit `dyn` are deprecated
+error[E0782]: trait objects without an explicit `dyn` are deprecated
   --> $DIR/dyn-trait-sugg-2021.rs:10:5
    |
 LL |     Foo::hi(123);
@@ -6,4 +6,4 @@ LL |     Foo::hi(123);
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0783`.
+For more information about this error, try `rustc --explain E0782`.