Add a i18n check in pre-commit for JS files (#37793)

lint-staged.config.js

@@ -5,6 +5,10 @@ const config = {
   '*.{css,scss}': 'stylelint --fix',
   '*.haml': 'bin/haml-lint -a',
   '**/*.ts?(x)': () => 'tsc -p tsconfig.json --noEmit',
+  'app/javascript/**/*.{js,jsx,ts,tsx}': () => [
+    `yarn i18n:extract`,
+    'git diff --exit-code app/javascript/mastodon/locales/en.json',
+  ],
 };
 
 module.exports = config;