Nightly lints and small tweaks (#12456)

Let chains available in 1.88 :D new clippy lints coming up in future
releases.

libs/proxy/postgres-protocol2/src/authentication/sasl.rs

@@ -52,7 +52,7 @@ pub(crate) async fn hi(str: &[u8], salt: &[u8], iterations: u32) -> [u8; 32] {
         }
         // yield every ~250us
         // hopefully reduces tail latencies
-        if i % 1024 == 0 {
+        if i.is_multiple_of(1024) {
             yield_now().await
         }
     }