Add brief note about justified navs being unsupported to fix twbs#14598

docs/_includes/components/navbar.html

@@ -3,6 +3,7 @@ <h1 id="navbar" class="page-header">Navbar</h1>
 
   <h2 id="navbar-default">Default navbar</h2>
   <p>Navbars are responsive meta components that serve as navigation headers for your application or site. They begin collapsed (and are toggleable) in mobile views and become horizontal as the available viewport width increases.</p>
+  <p><strong class="text-danger">Justified navbar nav links are currently not supported.</strong></p>
 
   <div class="bs-callout bs-callout-warning" id="callout-navbar-overflow">
     <h4>Overflowing content</h4>