Dropdown docs: Tweak .dropup copy

docs/_includes/components/dropdowns.html

@@ -4,7 +4,7 @@
   <p class="lead">Toggleable, contextual menu for displaying lists of links. Made interactive with the <a href="../javascript/#dropdowns">dropdown JavaScript plugin</a>.</p>
 
   <h3 id="dropdowns-example">Example</h3>
-  <p>Wrap the dropdown's trigger and the dropdown menu within <code>.dropdown</code>, or another element that declares <code>position: relative;</code>. Then add the menu's HTML. Dropdown menus can also be triggered above elements by adding <code>.dropup</code> to the parent.</p>
+  <p>Wrap the dropdown's trigger and the dropdown menu within <code>.dropdown</code>, or another element that declares <code>position: relative;</code>. Then add the menu's HTML. Dropdown menus can be changed to expand upwards (instead of downwards) by adding <code>.dropup</code> to the parent.</p>
   <div class="bs-example" data-example-id="static-dropdown">
     <div class="dropdown clearfix">
       <button class="btn btn-default dropdown-toggle" type="button" id="dropdownMenu1" data-toggle="dropdown" aria-expanded="true">