Hide hamburger menu button on mobile when there are no menu items (#254)

* Hide hamburger menu button on mobile when there are no menu items fix 253

* Fix template identation

Co-authored-by: Luiz F. A. de Prá <luizdepra@users.noreply.github.com>

layouts/partials/header.html

@@ -3,6 +3,7 @@
     <a class="navigation-title" href="{{ .Site.BaseURL | relLangURL }}">
       {{ .Site.Title }}
     </a>
+    {{ if or .Site.Menus.main .Site.IsMultiLingual }}
     <input type="checkbox" id="menu-toggle" />
     <label class="menu-button float-right" for="menu-toggle"><i class="fas fa-bars"></i></label>
     <ul class="navigation-list">
@@ -31,5 +32,6 @@
         {{ end }}
       {{ end }}
     </ul>
+    {{ end }}
   </section>
 </nav>