docs: added fiddle support for code samples (#26501)

* docs: added fiddle support for code samples in quick start guide and features

* docs: removed excessive fiddle links for not final steps

* docs: added eof newlines to fiddle examples

* docs: reworked fiddle examples to be more self-sufficient

* docs: reworked fiddle examples according to mentions

* docs: changed http to https in the offscreen rendering fiddle

* docs: fix recent documents fiddle to be more consistent

docs/fiddles/features/offscreen-rendering/main.js

@@ -0,0 +1,28 @@
+const { app, BrowserWindow } = require('electron')
+const fs = require('fs')
+
+app.disableHardwareAcceleration()
+
+let win
+
+app.whenReady().then(() => {
+  win = new BrowserWindow({ webPreferences: { offscreen: true } })
+  win.loadURL('https://github.com')
+  win.webContents.on('paint', (event, dirty, image) => {
+    fs.writeFileSync('ex.png', image.toPNG())
+  })
+  win.webContents.setFrameRate(60)
+  console.log(`The screenshot has been successfully saved to ${process.cwd()}/ex.png`)
+})
+
+app.on('window-all-closed', () => {
+  if (process.platform !== 'darwin') {
+    app.quit()
+  }
+})
+
+app.on('activate', () => {
+  if (BrowserWindow.getAllWindows().length === 0) {
+    createWindow()
+  }
+})