Add v5.1.0 docs (#34675)

docs/5.1/examples/offcanvas-navbar/offcanvas.js

@@ -0,0 +1,7 @@
+(function () {
+  'use strict'
+
+  document.querySelector('#navbarSideCollapse').addEventListener('click', function () {
+    document.querySelector('.offcanvas-collapse').classList.toggle('open')
+  })
+})()