📝 Update API documentation to ES6 [ci skip]

docs/api/content-tracing.md

@@ -8,7 +8,7 @@ This module does not include a web interface so you need to open
 result.
 
 ```javascript
-const contentTracing = require('electron').contentTracing;
+const { contentTracing } = require('electron');
 
 const options = {
   categoryFilter: '*',
@@ -18,8 +18,8 @@ const options = {
 contentTracing.startRecording(options, function() {
   console.log('Tracing started');
 
-  setTimeout(function() {
-    contentTracing.stopRecording('', function(path) {
+  setTimeout(() => {
+    contentTracing.stopRecording('', (path) => {
       console.log('Tracing data recorded to ' + path);
     });
   }, 5000);