Improve timeline entries for WIP prefix changes in pull requests (#36518)

Add new timeline event types when the WIP prefix is added or removed,
replacing the previous ugly title change messages.

Fixes: https://github.com/go-gitea/gitea/issues/36517

---------

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

templates/repo/issue/view_content/comments.tmpl

@@ -1,5 +1,5 @@
 {{template "base/alert"}}
-{{range .Issue.Comments}}
+{{range $comment := .Issue.Comments}}
 	{{if call $.ShouldShowCommentType .Type}}
 		{{$createdStr:= DateUtils.TimeSince .CreatedUnix}}
 
@@ -220,11 +220,11 @@
 			</div>
 		{{else if eq .Type 10}}
 			<div class="timeline-item event" id="{{.HashTag}}">
-				<span class="badge">{{svg "octicon-pencil"}}</span>
+				<span class="badge">{{ctx.RenderUtils.RenderTimelineEventBadge $comment}}</span>
 				{{template "shared/user/avatarlink" dict "user" .Poster}}
 				<span class="comment-text-line">
 					{{template "shared/user/authorlink" .Poster}}
-					{{ctx.Locale.Tr "repo.issues.change_title_at" (.OldTitle|ctx.RenderUtils.RenderEmoji) (.NewTitle|ctx.RenderUtils.RenderEmoji) $createdStr}}
+					{{ctx.RenderUtils.RenderTimelineEventComment $comment $createdStr}}
 				</span>
 			</div>
 		{{else if eq .Type 11}}