fix async issues

ext/bg/js/search-query-parser-generator.js

@@ -20,10 +20,9 @@
 class QueryParserGenerator {
     constructor() {
         this._templateHandler = null;
-        this._initialize();
     }
 
-    async _initialize() {
+    async prepare() {
         const html = await apiGetQueryParserTemplatesHtml();
         this._templateHandler = new TemplateHandler(html);
     }

ext/bg/js/search-query-parser.js

@@ -31,6 +31,10 @@ class QueryParser extends TextScanner {
         this.queryParserGenerator = new QueryParserGenerator();
     }
 
+    async prepare() {
+        await this.queryParserGenerator.prepare();
+    }
+
     onError(error) {
         logError(error, false);
     }

ext/bg/js/search.js

@@ -49,6 +49,8 @@ class DisplaySearch extends Display {
         try {
             await this.initialize();
 
+            await this.queryParser.prepare();
+
             const {queryParams: {query='', mode=''}} = parseUrl(window.location.href);
 
             if (this.search !== null) {