use AppUrl to replace HTMLURL

Author: wxiaoguang

templates/repo/issue/view_content/pull_merge_instruction.tmpl

@@ -5,8 +5,7 @@
 	<div class="ui secondary segment">
 		{{if eq $.Issue.PullRequest.Flow 0}}
 		<div>git checkout -b {{if ne $.Issue.PullRequest.HeadRepo.ID $.Issue.PullRequest.BaseRepo.ID}}{{$.Issue.PullRequest.HeadRepo.OwnerName}}-{{end}}{{$.Issue.PullRequest.HeadBranch}} {{$.Issue.PullRequest.BaseBranch}}</div>
-		{{/* the only legacy HTMLURL used in template, which doesn't affect users too much and is very diffcult to fix */}}
-		<div>git pull {{if ne $.Issue.PullRequest.HeadRepo.ID $.Issue.PullRequest.BaseRepo.ID}}{{$.Issue.PullRequest.HeadRepo.HTMLURL}}{{else}}origin{{end}} {{$.Issue.PullRequest.HeadBranch}}</div>
+		<div>git pull {{if ne $.Issue.PullRequest.HeadRepo.ID $.Issue.PullRequest.BaseRepo.ID}}{{URLJoin AppUrl $.Issue.PullRequest.HeadRepo.Link}}{{else}}origin{{end}} {{$.Issue.PullRequest.HeadBranch}}</div>
 		{{else}}
 		<div>git fetch origin {{$.Issue.PullRequest.GetGitRefName}}:{{$.Issue.PullRequest.HeadBranch}}</div>
 		{{end}}