dashboard/app: make bug lists collapsible

The bug lists on the main page are extremely long,
it's very hard to navigate between them.
Make bug lists collapsible.

Author: dvyukov

dashboard/app/templates/main.html

@@ -19,7 +19,13 @@
 	{{end}}
 	{{template "bug_filter" $.BugFilter}}
 	{{range $group := $.Groups}}
-		{{template "bug_list" $group}}
+		<details open>
+			<summary class="bug_list_caption">
+				{{$group.Caption}} ({{len $group.Bugs}})
+				<a id="{{$group.Fragment}}" href="#{{$group.Fragment}}">🔗</a>
+			</summary>
+			{{template "bug_list" $group}}
+		</details>
 	{{end}}
 </body>
 </html>

dashboard/app/templates/templates.html

@@ -164,16 +164,6 @@ <h1><a href="/{{$.Namespace}}">syzbot</a></h1>
 {{if .}}
 {{if .Bugs}}
 <table class="list_table">
-	{{if $.Caption}}
-		{{if $.Fragment}}
-			<caption id="{{$.Fragment}}"><a class="plain" href="#{{$.Fragment}}">
-		{{else}}
-			<caption>
-		{{end}}
-		{{$.Caption}} ({{len $.Bugs}}):
-		{{if $.Fragment}}</a>{{end}}
-		</caption>
-	{{end}}
 	<thead>
 	<tr>
 		{{if $.ShowNamespace}}

pkg/html/pages/style.css

@@ -66,6 +66,13 @@ table td, table th {
 	color: #375EAB;
 }
 
+.bug_list_caption {
+	font-weight: bold;
+	font-size: large;
+	color: #375EAB;
+	cursor: pointer;
+}
+
 .position_table {
 	border: 0px;
 	margin: 0px;