Add search event to Hydro (#16157)

* Add search event

* Lint fixes

Author: heiskr

javascripts/search.js

@@ -1,5 +1,6 @@
+import { sendEvent } from './events'
 const instantsearch = require('instantsearch.js').default
-const { searchBox, hits, configure } = require('instantsearch.js/es/widgets')
+const { searchBox, hits, configure, analytics } = require('instantsearch.js/es/widgets')
 const algoliasearch = require('algoliasearch')
 const searchWithYourKeyboard = require('search-with-your-keyboard')
 const querystring = require('querystring')
@@ -162,6 +163,15 @@ export default function () {
         autofocus: (hasStandaloneSearch()) && !window.location.hash.length,
         showReset: false,
         showSubmit: false
+      }),
+      analytics({
+        pushFunction (params, state, results) {
+          sendEvent({
+            type: 'search',
+            search_query: results.query
+            // search_context
+          })
+        }
       })
     ]
   )