Fix missing AppSubUrl in some templates (#5020)

templates/explore/repo_list.tmpl

@@ -20,7 +20,7 @@
 			{{if .Topics }}
 				<div>
 				{{range .Topics}}
-					{{if ne . "" }}<a href="/explore/repos?q={{.}}&topic=1"><div class="ui green basic label topic">{{.}}</div></a>{{end}}
+					{{if ne . "" }}<a href="{{AppSubUrl}}/explore/repos?q={{.}}&topic=1"><div class="ui green basic label topic">{{.}}</div></a>{{end}}
 				{{end}}
 				</div>
 			{{end}}

templates/repo/home.tmpl

@@ -24,7 +24,7 @@
 			{{end}}
 		</div>
 		<div class="ui repo-topic" id="repo-topic">
-		{{range .Topics}}<a class="ui green basic label topic" style="cursor:pointer;" href="/explore/repos?q={{.Name}}&topic=1">{{.Name}}</a>{{end}}
+		{{range .Topics}}<a class="ui green basic label topic" style="cursor:pointer;" href="{{AppSubUrl}}/explore/repos?q={{.Name}}&topic=1">{{.Name}}</a>{{end}}
 		{{if .IsRepositoryAdmin}}<a id="manage_topic" style="cursor:pointer;margin-left:10px;">{{.i18n.Tr "repo.topic.manage_topics"}}</a>{{end}}
 		</div>
 		{{if .IsRepositoryAdmin}}