docs: add clipboard Fiddle examples (#20445)

* docs: add clipboard paste Fiddle example

* docs: add clipboard copy Fiddle example

* docs: add appropriate title to Fiddles

Co-Authored-By: John Kleinschmidt <jkleinsc@github.com>

docs/fiddles/system/clipboard/paste/renderer.js

@@ -0,0 +1,9 @@
+const { clipboard } = require('electron')
+
+const pasteBtn = document.getElementById('paste-to')
+
+pasteBtn.addEventListener('click', () => {
+  clipboard.writeText('What a demo!')
+  const message = `Clipboard contents: ${clipboard.readText()}`
+  document.getElementById('paste-from').innerHTML = message
+})