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/keyboard-shortcuts.md

@@ -82,7 +82,7 @@ listen for the `keyup` and `keydown` [DOM events][dom-events] inside the
 renderer process using the [addEventListener() API][addEventListener-api].
 
 ```javascript fiddle='docs/fiddles/features/keyboard-shortcuts/web-apis|focus=renderer.js'
-function handleKeyPress(event) {
+const handleKeyPress = (event) => {
   // You can put code here to handle the keypress.
   document.getElementById("last-keypress").innerText = event.key;
   console.log(`You pressed ${event.key}`);