Update RELEASES.md

Co-authored-by: lcnr <rust@lcnr.de>

Author: Mark-Simulacrum

RELEASES.md

@@ -16,6 +16,9 @@ Language
 - [Warn against refining impls of crate-private traits with `refining_impl_trait` lint.](https://github.com/rust-lang/rust/pull/121720/)
 - [Stabilize associated type bounds (RFC 2289).](https://github.com/rust-lang/rust/pull/122055/)
 - [Stabilize importing `main` from other modules or crates.](https://github.com/rust-lang/rust/pull/122060/)
+- [Check return types of function types for well-formedness](https://github.com/rust-lang/rust/pull/115538)
+- [Rework `impl Trait` lifetime inference](https://github.com/rust-lang/rust/pull/116891/)
+- [Change inductive trait solver cycles to be ambiguous](https://github.com/rust-lang/rust/pull/122791)
 
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