Greatly speed up search index load

Author: GuillaumeGomez

src/renderer/html_handlebars/search.rs

@@ -66,7 +66,7 @@ pub fn create_files(
     if search_config.copy_js {
         static_files.add_builtin(
             "searchindex.js",
-            format!("Object.assign(window.search, {});", index).as_bytes(),
+            format!("window.search = JSON.parse({:?});", index).as_bytes(),
         );
         static_files.add_builtin("searcher.js", searcher::JS);
         static_files.add_builtin("mark.min.js", searcher::MARK_JS);