fix brok btn-dropdowns links

docs/docs.html

@@ -2802,7 +2802,7 @@ For example, <code>&lt;section&gt;</code> should be wrapped as inline.
     </div>
     <p class="lead">Use any button to trigger a dropdown menu by placing it within a <code>.btn-group</code> and providing the proper menu markup. Requires the <a href="./javascript.html#dropdowns">Bootstrap dropdown plugin</a>.</p>
 
-    <h3 id="btn-dropdown-single">Single button dropdowns</h3>
+    <h3 id="btn-dropdowns-single">Single button dropdowns</h3>
     <p>Turn a button into dropdown toggle with some basic markup changes.</p>
     <div class="bs-docs-example">
       <div class="btn-toolbar" style="margin-bottom: 10px;">
@@ -2874,7 +2874,7 @@ For example, <code>&lt;section&gt;</code> should be wrapped as inline.
 </div>
 {% endhighlight %}
 
-    <h3 id="btn-dropdown-split">Split button dropdowns</h3>
+    <h3 id="btn-dropdowns-split">Split button dropdowns</h3>
     <p>Similarly, create split button dropdowns with the same markup changes, only with a separate button.</p>
     <div class="bs-docs-example">
       <div class="btn-toolbar" style="margin: 0;">