Rollup merge of #126314 - lcnr:fix-relnotes, r=pietroalbini

fix RELEASES: we do not support upcasting to auto traits

#119338 does not actually support casts from `dyn Trait` to `dyn Auto`, only from `dyn Trait` to `dyn Trait + Auto`. The following test does not compile

```rust
trait Trait: Send {}
impl<T: Send> Trait for T {}

fn foo() {
    let x: &i32 = &1;
    let y = x as &dyn Trait as &dyn Send;
}
```
it actually also doesn't compile with `feature(trait_upcasting)`, opened #126313 for that

r? `@Mark-Simulacrum` `@cuviper`

RELEASES.md

@@ -147,7 +147,7 @@ Language
 - [Split `refining_impl_trait` lint into `_reachable`, `_internal` variants](https://github.com/rust-lang/rust/pull/121720/)
 - [Remove unnecessary type inference when using associated types inside of higher ranked `where`-bounds](https://github.com/rust-lang/rust/pull/119849)
 - [Weaken eager detection of cyclic types during type inference](https://github.com/rust-lang/rust/pull/119989)
-- [`trait Trait: Auto {}`: allow upcasting from `dyn Trait` to `dyn Auto`](https://github.com/rust-lang/rust/pull/119338)
+- [`trait Trait: Auto {}`: allow upcasting from `dyn Trait` to `dyn Trait + Auto`](https://github.com/rust-lang/rust/pull/119338)
 
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