docs: update to the use of arrow functions in line with the style guide (#30194)

* docs: Update to the use of arrow functions in line with the style guide

* docs: Fixed unmatched bracket typo in previous commit 9ebe3e58f7948c6636d77f3c58a2693683b69691

* fix linting

Co-authored-by: Cheng Zhao <zcbenz@gmail.com>

docs/tutorial/security.md

@@ -216,7 +216,7 @@ access to a `window.readConfig()` method, but no Node.js features.
 ```js
 const { readFileSync } = require('fs')
 
-window.readConfig = function () {
+window.readConfig = () => {
   const data = readFileSync('./config.json')
   return data
 }