Add keyboard shortcut to focus search field (#31702)

* Documentation: Add slash key event to focus the input search.

* Add little tag for keyboard shortcut in the search field

* Use ctrl / as keyboard shortcut

* Update search.js

Co-authored-by: chuckrincon <chuckrincon@gmail.com>
Co-authored-by: Patrick H. Lauke <redux@splintered.co.uk>
Co-authored-by: XhmikosR <xhmikosr@gmail.com>

site/assets/js/search.js

@@ -12,6 +12,13 @@
   var inputElement = document.getElementById('search-input')
   var siteDocsVersion = inputElement.getAttribute('data-docs-version')
 
+  document.addEventListener('keydown', function (event) {
+    if (event.ctrlKey && event.key === '/') {
+      event.preventDefault()
+      inputElement.focus()
+    }
+  })
+
   function getOrigin() {
     var location = window.location
     var origin = location.origin