prevent navbar text wrapping

When a navbar item has multiple words, and there are enough navbar item to
cause the flexbox to be full at reduced window widths without transitioning
through the lower media breakpoint, the navbar link name can wrap, which causes
the alignment of all navbar items to break.

This change forbids navbar text wrapping even at bigger screen sizes.

assets/scss/_nav.scss

@@ -56,6 +56,10 @@
         font-weight: $font-weight-bold;
     }
 
+    .navbar-nav {
+        white-space: nowrap;
+    }
+
     // For .td-search__input styling, see _search.scss
 
     .dropdown {
@@ -81,9 +85,7 @@
             .navbar-nav {
                 padding-bottom: 2rem;
                 overflow-x: auto;
-                white-space: nowrap;
                 -webkit-overflow-scrolling: touch;
-
             }
         }
     }