Rust 1.86.0 lints (#7254)

Implement lints for the new Rust compiler version 1.86.0.

beacon_node/beacon_chain/src/block_verification.rs

@@ -5,7 +5,7 @@
 //! - Verification for gossip blocks (i.e., should we gossip some block from the network).
 //! - Verification for normal blocks (e.g., some block received on the RPC during a parent lookup).
 //! - Verification for chain segments (e.g., some chain of blocks received on the RPC during a
-//!    sync).
+//!   sync).
 //!
 //! The primary source of complexity here is that we wish to avoid doing duplicate work as a block
 //! moves through the verification process. For example, if some block is verified for gossip, we