GORISCV64=rva20u64 accepted to include compressed instructions

The accepted proposal to fold compressed instructions into GORISCV64=rva20u64 leads the day, cleaning up an ambiguity left over from the original RISC-V baseline discussion and nudging the default a little closer to what real rva20 hardware actually runs. On the side, the x/tools analysis framework resurfaces on Hacker News as a reminder of how much modular static analysis quietly rides along with the toolchain, and someone shipped a pure-Go WebP codec with no cgo, libwebp, or wasm in sight, which is the kind of yak-shave that pays off for years.