give all docs callouts IDs

[skip sauce]

docs/_includes/js/modal.html

@@ -10,7 +10,7 @@
     <h4>Modal markup placement</h4>
     <p>Always try to place a modal's HTML code in a top-level position in your document to avoid other components affecting the modal's appearance and/or functionality.</p>
   </div>
-  <div class="bs-callout bs-callout-warning">
+  <div class="bs-callout bs-callout-warning" id="callout-modal-mobile-caveats">
     <h4>Mobile device caveats</h4>
     <p>There are some caveats regarding using modals on mobile devices. <a href="../getting-started/#support-fixed-position-keyboards">See our browser support docs</a> for details.</p>
   </div>
@@ -134,13 +134,13 @@
 </div>
 {% endhighlight %}
 
-  <div class="bs-callout bs-callout-warning">
+  <div class="bs-callout bs-callout-warning" id="callout-modal-accessibility">
     <h4>Make modals accessible</h4>
     <p>Be sure to add <code>role="dialog"</code> to <code>.modal</code>, <code>aria-labelledby="myModalLabel"</code> attribute to reference the modal title, and <code>aria-hidden="true"</code> to tell assistive technologies to skip the modal's DOM elements.</p>
     <p>Additionally, you may give a description of your modal dialog with <code>aria-describedby</code> on <code>.modal</code>.</p>
   </div>
 
-  <div class="bs-callout bs-callout-info">
+  <div class="bs-callout bs-callout-info" id="callout-modal-youtube">
     <h4>Embedding YouTube videos</h4>
     <p>Embedding YouTube videos in modals requires additional JavaScript not in Bootstrap to automatically stop playback and more. <a href="http://stackoverflow.com/questions/18622508/bootstrap-3-and-youtube-in-modal">See this helpful Stack Overflow post</a> for more information.</p>
   </div>