JS docs: add Options, Methods, Events subsections to nav sidebar

docs/_includes/js/collapse.html

@@ -161,7 +161,7 @@
 $('.collapse').collapse()
 {% endhighlight %}
 
-  <h3>Options</h3>
+  <h3 id="collapse-options">Options</h3>
   <p>Options can be passed via data attributes or JavaScript. For data attributes, append the option name to <code>data-</code>, as in <code>data-parent=""</code>.</p>
   <div class="table-responsive">
     <table class="table table-bordered table-striped">
@@ -190,7 +190,7 @@ $('.collapse').collapse()
     </table>
   </div><!-- /.table-responsive -->
 
-  <h3>Methods</h3>
+  <h3 id="collapse-methods">Methods</h3>
 
   <h4>.collapse(options)</h4>
   <p>Activates your content as a collapsible element. Accepts an optional options <code>object</code>.
@@ -209,7 +209,7 @@ $('#myCollapsible').collapse({
   <h4>.collapse('hide')</h4>
   <p>Hides a collapsible element.</p>
 
-  <h3>Events</h3>
+  <h3 id="collapse-events">Events</h3>
   <p>Bootstrap's collapse class exposes a few events for hooking into collapse functionality.</p>
   <div class="table-responsive">
     <table class="table table-bordered table-striped">