godoc: add separators between quick reference topics

R=bradfitz, dangabrad
CC=golang-dev
https://golang.org/cl/3433042

doc/all.css

@@ -92,6 +92,9 @@ h1#title {
 #nav-main .quickref {
   color: #444;
 }
+#nav-main .quickref .sep {
+  color: #999;
+}
 #search {
   width: 100px;
   margin-left: 0.5em;

lib/godoc/godoc.html

@@ -25,13 +25,13 @@
         <form method="GET" action="/search">
         {.section PkgRoots}
         {.repeated section PkgRoots}
-        <a href="/pkg/{@|html-esc}">{@|html-esc}</a>
+        <a href="/pkg/{@|html-esc}">{@|html-esc}</a> <span class="sep">|</span>
         {.end}
         {.or}
         References:
         {.end}
-        <a href="/pkg/">Packages</a>
-        <a href="/cmd/">Commands</a>
+        <a href="/pkg/">Packages</a> <span class="sep">|</span>
+        <a href="/cmd/">Commands</a> <span class="sep">|</span>
         <a href="/doc/go_spec.html">Specification</a>
         <input id="search" type="text" name="q" value="{.section Query}{Query|html-esc}{.or}code search{.end}" class="{.section Query}{.or}inactive{.end}" />
         </form>