Rename header.scala.html to menu.scala.html

src/main/twirl/repo/blob.scala.html

@@ -7,7 +7,7 @@
 @import context._
 @import view.helpers._
 @html.main(s"${repository.owner}/${repository.name}", Some(repository)) {
-  @html.header("code", repository){
+  @html.menu("code", repository){
     @tab(branch, repository, "files")
     <div class="head">
       <a href="@url(repository)/tree/@encodeRefName(branch)">@repository.name</a> /