Added @stylistic/eslint-plugin-js as dev dependency to lint trailing …

…whitespace

eslint.config.mjs

@@ -1,5 +1,6 @@
 import js from '@eslint/js'
 import globals from 'globals'
+import stylisticJS from '@stylistic/eslint-plugin-js'
 import json from '@eslint/json'
 import markdown from '@eslint/markdown'
 import * as regexp from 'eslint-plugin-regexp'
@@ -9,10 +10,11 @@ export default [
     {
         files: ['**/*.js', '**/*.mjs'],
         languageOptions: { ecmaVersion: 'latest', sourceType: 'script', globals: { ...globals.browser, ...globals.greasemonkey }},
-        plugins: { regexp },
+        plugins: { regexp, 'js-styles': stylisticJS },
         rules: {
             ...js.configs.recommended.rules, ...regexp.configs['flat/recommended'].rules,
             'indent': 'off', 'no-unexpected-multiline': 'off', 'key-spacing': 'off', // allow whitespace anywhere
+            'js-styles/no-trailing-spaces': 'error', // ...except at ends of lines
             'quotes': ['error', 'single'], // enforce single quotes for string literals
             'comma-dangle': ['error', 'never'], // enforce no trailing commas in arrays or objects
             'no-async-promise-executor': 'off', // allow promise executor functions to be async (to accomodate await lines)

package.json

@@ -25,6 +25,7 @@
   "devDependencies": {
     "@eslint/json": "^0.7.0",
     "@eslint/markdown": "^6.2.1",
+    "@stylistic/eslint-plugin-js": "^2.11.0",
     "eslint": "^9.15.0",
     "eslint-plugin-regexp": "^2.7.0",
     "eslint-plugin-yml": "^1.15.0",