Test fixtures for JavaScript syntax rules.
Each subdirectory corresponds to one builtin JS rule and contains a `match.js` file (expected to produce findings) and a `no_match.js` file (expected to produce zero findings). Rules covered: `js/console-log`, `js/module-let`, `js/unnecessary-const`, `js/var-declaration`, `js/typeof-string`, `js/eq-null`, `js/no-await-in-loop`, `js/no-prototype-builtins`, `js/prefer-optional-chain`.