Fix missing title and filter in issue sidebar project menu (#22557)

These exist in the new issue form but were seemingly forgotten here.

templates/repo/issue/view_content/sidebar.tmpl

@@ -212,6 +212,13 @@
 					{{end}}
 				</a>
 				<div class="menu" data-action="update" data-issue-id="{{$.Issue.ID}}" data-update-url="{{$.RepoLink}}/issues/projects">
+					<div class="header" style="text-transform: none;font-size:16px;">{{.locale.Tr "repo.issues.new.add_project_title"}}</div>
+					{{if or .OpenProjects .ClosedProjects}}
+					<div class="ui icon search input">
+						<i class="icon df ac jc">{{svg "octicon-search" 16}}</i>
+						<input type="text" placeholder="{{.locale.Tr "repo.issues.filter_projects"}}">
+					</div>
+					{{end}}
 					<div class="no-select item">{{.locale.Tr "repo.issues.new.clear_projects"}}</div>
 					{{if .OpenProjects}}
 						<div class="divider"></div>