[$] Safe self-referential data structures in kernel Rust

Self-referential structures that can be used without unsafe code have posed a problem for Rust for years. There are many cases where a self-referential data structure is the elegant algorithmic choice, but implementing it in accordance with Rust's lifetime rules is all but impossible. At Kangrejos 2026, Gary Guo presented a clever solution to the problem in the context of the kernel's pin_init crate, which helps with the creation of immovable data structures, typically for interoperability with C. Guo's changes could help remove most of the unsafe code related to lifetimes in the Nova driver and, eventually, other Rust components.