Display latest sync time for pull mirrors on the repo page (#28712)

Fixes #25168

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Co-authored-by: delvh <dev.lh@web.de>

templates/repo/header.tmpl

@@ -28,6 +28,13 @@
 						<div class="repo-icon" data-tooltip-content="{{ctx.Locale.Tr "repo.desc.template"}}">{{svg "octicon-repo-template" 18}}</div>
 					{{end}}
 				</div>
+				{{if $.PullMirror}}
+					<div class="fork-flag">
+						{{ctx.Locale.Tr "repo.mirror_from"}}
+						<a target="_blank" rel="noopener noreferrer" href="{{$.PullMirror.RemoteAddress}}">{{$.PullMirror.RemoteAddress}}</a>
+						{{if $.PullMirror.UpdatedUnix}}{{ctx.Locale.Tr "repo.mirror_sync"}} {{TimeSinceUnix $.PullMirror.UpdatedUnix ctx.Locale}}{{end}}
+					</div>
+				{{end}}
 			</div>
 			{{if not (or .IsBeingCreated .IsBroken)}}
 				<div class="repo-buttons">