fix(highlight): wrong parsing between client and server (#183)

BREAKING CHANGE:

We remove the timestamp present in our highlight preTag and postTag. If you were using regex to parse the
highlighting results then you'll need to adapt it as now it's only "ais-highlight".

packages/react-instantsearch/src/core/createInstantSearchServer.js

@@ -9,6 +9,7 @@ import ReactDom from 'react-dom/server';
 import { getIndex, hasMultipleIndex } from './indexUtils';
 import { isEmpty } from 'lodash';
 import cis from './createInstantSearch';
+import highlightTags from './highlightTags.js';
 
 const createInstantSearch = function(algoliasearch) {
   const InstantSearch = cis(algoliasearch, {
@@ -48,7 +49,7 @@ const createInstantSearch = function(algoliasearch) {
             searchParameter.props,
             searchParameter.searchState
           ),
-        new SearchParameters({ index: indexName })
+        new SearchParameters({ index: indexName, ...highlightTags })
       );
 
     const mergedSearchParameters = searchParameters

packages/react-instantsearch/src/core/highlightTags.js

@@ -1,6 +1,4 @@
-const timestamp = Date.now().toString();
-
 export default {
-  highlightPreTag: `<ais-highlight-${timestamp}>`,
-  highlightPostTag: `</ais-highlight-${timestamp}>`,
+  highlightPreTag: `<ais-highlight>`,
+  highlightPostTag: `</ais-highlight>`,
 };