Merge pull request #10594 from twbs/navbar-form-labels-warning

add same accessibility warning from .form-inline to .navbar-form docs

components.html

@@ -1562,6 +1562,11 @@ base_url: "../"
 </form>
 {% endhighlight %}
 
+<div class="bs-callout bs-callout-danger">
+  <h4>Always add labels</h4>
+  <p>Screen readers will have trouble with your forms if you don't include a label for every input. For these inline navbar forms, you can hide the labels using the <code>.sr-only</code> class.</p>
+</div>
+
 
     <h2 id="navbar-buttons">Buttons</h2>
     <p>For buttons not residing in a <code>&lt;form&gt;</code>, add this class to vertically center buttons within a navbar.</p>