docs: handle opening links in the default browser in main.js (#39379)

docs: handle opening links in the default browser in the main process

docs/fiddles/menus/shortcuts/main.js

@@ -1,5 +1,5 @@
 // Modules to control application life and create native browser window
-const { app, BrowserWindow, globalShortcut, dialog } = require('electron')
+const { app, BrowserWindow, globalShortcut, dialog, shell } = require('electron')
 
 // Keep a global reference of the window object, if you don't, the window will
 // be closed automatically when the JavaScript object is garbage collected.
@@ -38,6 +38,12 @@ function createWindow () {
     // when you should delete the corresponding element.
     mainWindow = null
   })
+
+  // Open external links in the default browser
+  mainWindow.webContents.on('will-navigate', (event, url) => {
+    event.preventDefault()
+    shell.openExternal(url)
+  })
 }
 
 // This method will be called when Electron has finished