fix br display for packages curls (go-gitea#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 go-gitea#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>

templates/package/content/generic.tmpl

@@ -5,9 +5,9 @@
 			<div class="field">
 				<label>{{svg "octicon-terminal"}} {{.locale.Tr "packages.generic.download"}}</label>
 				<div class="markup"><pre class="code-block"><code>
-					{{- range .PackageDescriptor.Files -}}
-curl <gitea-origin-url data-url="{{AppSubUrl}}/api/packages/{{$.PackageDescriptor.Owner.Name}}/generic/{{$.PackageDescriptor.Package.Name}}/{{$.PackageDescriptor.Version.Version}}/{{.File.Name}}"></gitea-origin-url><br>
-					{{- end -}}
+{{- range .PackageDescriptor.Files -}}
+curl <gitea-origin-url data-url="{{AppSubUrl}}/api/packages/{{$.PackageDescriptor.Owner.Name}}/generic/{{$.PackageDescriptor.Package.Name}}/{{$.PackageDescriptor.Version.Version}}/{{.File.Name}}"></gitea-origin-url>
+{{end -}}
 				</code></pre></div>
 			</div>
 			<div class="field">