Change the color of issues/pulls list, merged is purple and closed is red (#6874)

Author: lunny

templates/repo/issue/list.tmpl

@@ -200,7 +200,7 @@
 						<input type="checkbox" data-issue-id={{.ID}}></input>
 					</div>
 					{{end}}
-					<div class="ui {{if .IsRead}}black{{else}}green{{end}} label">#{{.Index}}</div>
+					<div class="ui {{if .IsClosed}}{{if .IsPull}}{{if .PullRequest.HasMerged}}purple{{else}}red{{end}}{{else}}red{{end}}{{else}}{{if .IsRead}}black{{else}}green{{end}}{{end}} label">#{{.Index}}</div>
 					<a class="title has-emoji" href="{{$.Link}}/{{.Index}}">{{.Title}}</a>
 
                     {{if .IsPull }}