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/keyboard-shortcuts/interception-from-main/main.js

@@ -0,0 +1,13 @@
+const { app, BrowserWindow } = require('electron')
+
+app.whenReady().then(() => {
+  const win = new BrowserWindow({ width: 800, height: 600, webPreferences: { nodeIntegration: true } })
+
+  win.loadFile('index.html')
+  win.webContents.on('before-input-event', (event, input) => {
+    if (input.control && input.key.toLowerCase() === 'i') {
+      console.log('Pressed Control+I')
+      event.preventDefault()
+    }
+  })
+})