fix br display for packages curls (#23737)

fix br display for packages curls (#23737)

Before:
<img width="1403" alt="截屏2023-03-27 15 48 23"
src="https://user-images.githubusercontent.com/17645053/227875392-399debf7-db75-4d9a-9436-409f75447c65.png">
This happens because the `<br>` matches this
[rule](https://github.com/go-gitea/gitea/blob/e6e602fd8d35471f1e2f4a42669a1f17e76e0176/web_src/css/markup/content.css#L428),
which is not necessary here (This is introduced by #22861, did a quick
check, and this is the only place used `<br>` inside `<code>` from the
PR):
```css
.markup code br,
.markup tt br {
  display: none;
}
```

After:
<img width="1398" alt="截屏2023-03-27 15 46 50"
src="https://user-images.githubusercontent.com/17645053/227875244-b7fba432-b32c-42f7-9517-4e05bb2e64ea.png">

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>