docs: change examples in docs to use for..of and async/await (#14842)

docs/api/desktop-capturer.md

@@ -12,24 +12,28 @@ title is `Electron`:
 // In the renderer process.
 const { desktopCapturer } = require('electron')
 
-desktopCapturer.getSources({ types: ['window', 'screen'] }, (error, sources) => {
+desktopCapturer.getSources({ types: ['window', 'screen'] }, async (error, sources) => {
   if (error) throw error
-  for (let i = 0; i < sources.length; ++i) {
-    if (sources[i].name === 'Electron') {
-      navigator.mediaDevices.getUserMedia({
-        audio: false,
-        video: {
-          mandatory: {
-            chromeMediaSource: 'desktop',
-            chromeMediaSourceId: sources[i].id,
-            minWidth: 1280,
-            maxWidth: 1280,
-            minHeight: 720,
-            maxHeight: 720
+  for (const source in sources) {
+    if (source.name === 'Electron') {
+      try {
+        const stream = await navigator.mediaDevices.getUserMedia({
+          audio: false,
+          video: {
+            mandatory: {
+              chromeMediaSource: 'desktop',
+              chromeMediaSourceId: source.id,
+              minWidth: 1280,
+              maxWidth: 1280,
+              minHeight: 720,
+              maxHeight: 720
+            }
           }
-        }
-      }).then((stream) => handleStream(stream))
-        .catch((e) => handleError(e))
+        })
+        handleStream(stream)
+      } catch (e) {
+        handleError(e)
+      }
       return
     }
   }

docs/tutorial/using-selenium-and-webdriver.md

@@ -25,27 +25,25 @@ var assert = require('assert')
 
 var app = new Application({
   path: '/Applications/MyApp.app/Contents/MacOS/MyApp'
-})
-
-app.start().then(function () {
-  // Check if the window is visible
-  return app.browserWindow.isVisible()
-}).then(function (isVisible) {
-  // Verify the window is visible
-  assert.strictEqual(isVisible, true)
-}).then(function () {
-  // Get the window's title
-  return app.client.getTitle()
-}).then(function (title) {
-  // Verify the window's title
-  assert.strictEqual(title, 'My App')
-}).catch(function (error) {
-  // Log any failures
-  console.error('Test failed', error.message)
-}).then(function () {
+});
+
+(async () => {
+  await app.start()
+  try {
+    // Check if the window is visible
+    const isVisible = await app.browserWindow.isVisible()
+    // Verify the window is visible
+    assert.strictEqual(isVisible, true)
+    // Get the window's title
+    const title = await app.client.getTitle()
+    // Verify the window's title
+    assert.strictEqual(title, 'My App')
+  } catch (error) {
+    console.error('Test failed', error.message)
+  }
   // Stop the application
-  return app.stop()
-})
+  await app.stop()
+})()
 ```
 
 ## Setting up with WebDriverJs