fix: nonexistent navbar button aria-controls ID (#2268)

wowchemy/layouts/partials/navbar.html

@@ -30,7 +30,7 @@
 
     {{ if site.Menus.main }}
     <button type="button" class="navbar-toggler" data-toggle="collapse"
-            data-target="#navbar-content" aria-controls="navbar" aria-expanded="false" aria-label="{{ i18n "toggle_navigation" }}">
+            data-target="#navbar-content" aria-controls="navbar-content" aria-expanded="false" aria-label="{{ i18n "toggle_navigation" }}">
     <span><i class="fas fa-bars"></i></span>
     </button>
     {{ end }}