Replace some gt- classes with tw- (#29570)

Replace 18 `gt-` prefixes with `tw-` with perl replacement. I manually
checked them all with `rg` afterwards.

templates/repo/issue/view_content/comments.tmpl

@@ -562,7 +562,7 @@
 					{{end}}
 				</span>
 				{{if and .IsForcePush $.Issue.PullRequest.BaseRepo.Name}}
-				<span class="gt-float-right comparebox">
+				<span class="tw-float-right comparebox">
 					<a href="{{$.Issue.PullRequest.BaseRepo.Link}}/compare/{{PathEscape .OldCommit}}..{{PathEscape .NewCommit}}" rel="nofollow" class="ui compare label">{{ctx.Locale.Tr "repo.issues.force_push_compare"}}</a>
 				</span>
 				{{end}}

templates/repo/issue/view_content/comments_delete_time.tmpl

@@ -1,7 +1,7 @@
 {{if and .comment.Time (.ctxData.Repository.IsTimetrackerEnabled ctx)}} {{/* compatibility with time comments made before v1.14 */}}
 	{{if (not .comment.Time.Deleted)}}
 		{{if (or .ctxData.IsAdmin (and .ctxData.IsSigned (eq .ctxData.SignedUserID .comment.PosterID)))}}
-			<span class="gt-float-right">
+			<span class="tw-float-right">
 				<div class="ui mini modal issue-delete-time-modal" data-id="{{.comment.Time.ID}}">
 					<form method="post" class="delete-time-form" action="{{.ctxData.RepoLink}}/issues/{{.ctxData.Issue.Index}}/times/{{.comment.TimeID}}/delete">
 						{{.ctxData.CsrfTokenHtml}}