Prevent empty div when editing comment (#12404)

* Prevent empty div when editing comment

The template for attachments needs to remove whitespace and return empty when there are no attachments.

Fix #10220

templates/repo/issue/view_content/attachments.tmpl

@@ -1,4 +1,4 @@
-{{range .Attachments}}
+{{- range .Attachments -}}
 <div class="twelve wide column" style="padding: 6px;">
 	<a target="_blank" rel="noopener noreferrer" href="{{.DownloadURL}}" title='{{$.ctx.i18n.Tr "repo.issues.attachment.open_tab" .Name}}'>
 	{{if FilenameIsImage .Name}}
@@ -12,4 +12,4 @@
 <div class="four wide column" style="padding: 0px;">
 	<span class="ui text grey right">{{.Size | FileSize}}</span>
 </div>
-{{end}}
+{{end -}}