rbcop: RuboCop rewritten in Rust, about 14x faster in CI

rbcop is a drop-in replacement for RuboCop 1.92.2, written in Rust on Prism. It reads the same .rubocop.yml , takes the same command line and produces the same output, checked against RuboCop itself on nine large codebases: about two million offenses, zero differences, autocorrect included. In CI with a cold cache it runs about 14x faster than rubocop --parallel .