Milo: Show accurate pending build numbers for builder view.

milo/frontend/appengine/templates/pages/builder.html

 {{define "title"}}Builder {{ .Builder.Name }}{{end}}
 
 {{define "head"}}
 <link id="favicon" rel="shortcut icon"
       type="image/png" href="/static/common/favicon/milo-32.png">
 {{end}}
 
 {{define "blamelist"}}
 {{ if . }}
   {{ $nb := len . }}
@@ skipping 78 matching lines @@
       </li>
     {{ end }}
     </ul>
   {{ else }}
     <h2>No current builds</h2>
   {{ end }}
   </div>
 
   <div class="column">
   {{ if .Builder.PendingBuilds -}}
-    <h2>Pending Build Requests ({{len .Builder.PendingBuilds}}):</h2>
+                <h2>Pending Build Requests (
+                        {{- if gt .Builder.PendingBuildNum (len .Builder.PendingBuilds) -}}
+                                {{ .Builder.PendingBuildNum }} showing 
+                        {{ end -}}{{- len .Builder.PendingBuilds -}}):</h2>
     <ul>
     {{- range .Builder.PendingBuilds -}}
       <li>
         <small>({{- .PendingTime.Started | localTime "" }}, waiting {{ .PendingTime.Duration | humanDuration -}})</small>
         {{- with .Blame }}{{- template "blamelist" -}}{{- end -}}
       </li>
     {{- end -}}
     </ul>
   {{ else }}
     <h2>No Pending Build Requests</h2>
@@ skipping 71 matching lines @@
   <a href="{{ pagedURL .Request 50 "" }}">50</a>
   <a href="{{ pagedURL .Request 100 "" }}">100</a>
   <a href="{{ pagedURL .Request 200 "" }}">200</a>
   )
   {{ if .Builder.NextCursor }}
     <a href="{{ pagedURL .Request 0 .Builder.NextCursor}}">Next</a>
   {{ end }}
 </div>
 
 {{end}}