l10n(search): localization for the toggle tools button

inc/Ui/Search.php

@@ -168,8 +168,8 @@ class Search extends Ui
      */
     protected function addSearchAssistanceElements(Form $searchForm)
     {
-        // FIXME localize
-        $searchForm->addButton('toggleAssistant', 'toggle search assistant')
+        global $lang;
+        $searchForm->addButton('toggleAssistant', $lang['search_toggle_tools'])
             ->attr('type', 'button')
             ->addClass('toggleAssistant');
 

inc/lang/en/lang.php

@@ -72,6 +72,7 @@ $lang['nosecedit']             = 'The page was changed in the meantime, section
 $lang['searchcreatepage']      = 'If you didn\'t find what you were looking for, you can create or edit the page %s, named after your query, with the appropriate tool.';
 
 $lang['search_fullresults']    = 'Fulltext results';
+$lang['search_toggle_tools']   = 'Toggle search tools';
 $lang['search_exact_match']    = 'Exact match';
 $lang['search_starts_with']    = 'Starts with';
 $lang['search_ends_with']      = 'Ends with';