give all docs callouts IDs

[skip sauce]

docs/_includes/css/buttons.html

@@ -35,7 +35,7 @@
 <button type="button" class="btn btn-link">Link</button>
 {% endhighlight %}
 
-  <div class="bs-callout bs-callout-warning">
+  <div class="bs-callout bs-callout-warning" id="callout-buttons-color-accessibility">
     <h4>Conveying meaning to assistive technologies</h4>
     <p>Using color to add meaning to a button only provides a visual indication, which will not be conveyed to users of assistive technologies – such as screen readers. Ensure that information denoted by the color is either obvious from the content itself (the visible text of the button), or is included through alternative means, such as additional text hidden with the <code>.sr-only</code> class.</p>
   </div>
@@ -132,7 +132,7 @@
 <button type="button" class="btn btn-default btn-lg" disabled="disabled">Button</button>
 {% endhighlight %}
 
-  <div class="bs-callout bs-callout-danger">
+  <div class="bs-callout bs-callout-danger" id="callout-buttons-ie-disabled">
     <h4>Cross-browser compatibility</h4>
     <p>If you add the <code>disabled</code> attribute to a <code>&lt;button&gt;</code>, Internet Explorer 9 and below will render text gray with a nasty text-shadow that we cannot fix.</p>
   </div>
@@ -150,11 +150,11 @@
   <p>
     We use <code>.disabled</code> as a utility class here, similar to the common <code>.active</code> class, so no prefix is required.
   </p>
-  <div class="bs-callout bs-callout-warning">
+  <div class="bs-callout bs-callout-warning" id="callout-buttons-disabled-anchor">
     <h4>Link functionality caveat</h4>
     <p>This class uses <code>pointer-events: none</code> to try to disable the link functionality of <code>&lt;a&gt;</code>s, but that CSS property is not yet standardized and isn't fully supported in Opera 18 and below, or in Internet Explorer 11. In addition, even in browsers that do support <code>pointer-events: none</code>, keyboard navigation remains unaffected, meaning that sighted keyboard users and users of assistive technologies will still be able to activate these links. So to be safe, use custom JavaScript to disable such links.</p>
   </div>
-  <div class="bs-callout bs-callout-warning">
+  <div class="bs-callout bs-callout-warning" id="callout-buttons-context-usage">
     <h4>Context-specific usage</h4>
     <p>While button classes can be used on <code>&lt;a&gt;</code> and <code>&lt;button&gt;</code> elements, only <code>&lt;button&gt;</code> elements are supported within our nav and navbar components.</p>
   </div>
@@ -175,12 +175,12 @@
 <input class="btn btn-default" type="submit" value="Submit">
 {% endhighlight %}
 
-  <div class="bs-callout bs-callout-warning">
+  <div class="bs-callout bs-callout-warning" id="callout-buttons-anchor-accessibility">
     <h4>Links acting as buttons</h4>
     <p>If the <code>&lt;a&gt;</code> elements are used to act as buttons – triggering in-page functionality, rather than navigating to another document or section within the current page – they should also be given an appropriate <code>role="button"</code>.</p>
   </div>
 
-  <div class="bs-callout bs-callout-warning">
+  <div class="bs-callout bs-callout-warning" id="callout-buttons-ff-height">
     <h4>Cross-browser rendering</h4>
     <p>As a best practice, <strong>we highly recommend using the <code>&lt;button&gt;</code> element whenever possible</strong> to ensure matching cross-browser rendering.</p>
     <p>Among other things, there's <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=697451">a bug in Firefox &lt;30</a> that prevents us from setting the <code>line-height</code> of <code>&lt;input&gt;</code>-based buttons, causing them to not exactly match the height of other buttons on Firefox.</p>