godoc: move Examples above Index and make them both collapsable

R=golang-dev, dsymonds, bradfitz, r
CC=golang-dev
https://golang.org/cl/6591066

lib/godoc/package.html

@@ -37,10 +37,32 @@
 			</div>
 		</div>
 		{{example_html "" $.Examples $.FSet}}
+
+		{{if $.Examples}}
+		<div id="pkg-examples" class="toggleVisible">
+			<div class="collapsed">
+				<h2 class="toggleButton" title="Click to show Examples section">Examples ▹</h2>
+			</div>
+			<div class="expanded">
+				<h2 class="toggleButton" title="Click to hide Examples section">Examples ▾</h2>
+				<dl>
+				{{range $.Examples}}
+				<dd><a class="exampleLink" href="#example_{{.Name}}">{{example_name .Name}}</a></dd>
+				{{end}}
+				</dl>
+			</div>
+		</div>
+		{{end}}
 	
-		<h2 id="pkg-index">Index</h2>
+		<div id="pkg-index" class="toggleVisible">
+		<div class="collapsed">
+			<h2 class="toggleButton" title="Click to show Index section">Index ▹</h2>
+		</div>
+		<div class="expanded">
+			<h2 class="toggleButton" title="Click to hide Index section">Index ▾</h2>
+
 		<!-- Table of contents for API; must be named manual-nav to turn off auto nav. -->
-		<div id="manual-nav">
+			<div id="manual-nav">
 			<dl>
 			{{if .Consts}}
 				<dd><a href="#pkg-constants">Constants</a></dd>
@@ -67,16 +89,8 @@
 			{{if .Bugs}}
 				<dd><a href="#pkg-bugs">Bugs</a></dd>
 			{{end}}
-		</dl>
-
-		{{if $.Examples}}
-			<h4 id="pkg-examples">Examples</h4>
-			<dl>
-			{{range $.Examples}}
-			<dd><a class="exampleLink" href="#example_{{.Name}}">{{example_name .Name}}</a></dd>
-			{{end}}
 			</dl>
-		{{end}}
+			</div><!-- #manual-nav -->
 
 		{{with .Filenames}}
 			<h4>Package files</h4>
@@ -88,6 +102,8 @@
 			</span>
 			</p>
 		{{end}}
+		</div><!-- .expanded -->
+		</div><!-- #pkg-index -->
 	
 		{{with .Consts}}
 			<h2 id="pkg-constants">Constants</h2>