Fix file name in zoho editor

Fix file name in zoho editor in :
- in title
- in file name proposed with export tools

core/src/plugins/editor.zoho/class.ZohoEditor.php

@@ -147,7 +147,7 @@ public function switchAction($action, $httpVars, $filesVars)
                 'apikey' => $this->getFilteredOption("ZOHO_API_KEY", $repository),
                 'output' => 'url',
                 'lang' => "en",
-                'filename' => urlencode(basename($file)),
+                'filename' => SystemTextEncoding::toUTF8(basename($file)),
                 'persistence' => 'false',
                 'format' => $extension,
                 'mode' => 'normaledit',