GCC 16 debuts C++20 by default, adds Algol 68 and boosts diagnostics

GCC 16 now defaults to C++20 for C++ compilation, bringing new C++26 and C++23 features, and requires users depending on older standards to update build flags. The release adds an experimental Algol 68 compiler front end. GCC diagnostics receive major updates including HTML output and detailed SARIF reporting. Users benefit from broad improvements to language support, hardware compatibility, and parallel computing APIs.