Translation: Add missing entry for new "code" tab

We have new tab, but we had no entry. That's why it was showing "code"
(lowercase) as this is text id, where we were expecting properly title cased
"Code" to be shown in English version.

Also add Polish translation "code=Kod".

conf/locale/locale_zh-CN.ini

@@ -388,6 +388,7 @@ create_new_repo_command=从命令行创建一个新的仓库
 push_exist_repo=从命令行推送已经创建的仓库
 repo_is_empty=该仓库不包含任何内容，请稍后再进行访问！
 
+code=Code
 branch=分支
 tree=目录树
 filter_branch_and_tag=过滤分支或标签