Rust 1.78.0 released

Version1.78.0 of the Rust language has been released. Changes include a newmechanism for diagnostic attributes, changes to how assertions aroundunsafe blocks are handled, and more.

Rust now supports a #[diagnostic] attribute namespace toinfluence compiler error messages. These are treated as hints whichthe compiler is not required to use, and it is also not an error toprovide a diagnostic that the compiler doesn't recognize. Thisflexibility allows source code to provide diagnostics even whenthey're not supported by all compilers, whether those are differentversions or entirely different implementations.