Make Forms => Default styles code snippet the same as example

docs/base-css.html

@@ -842,7 +842,8 @@ For example, <code>section</code> should be wrapped as inline.
             <button type="submit" class="btn">Submit</button>
           </form>
 <pre class="prettyprint linenums">
-&lt;form class="well"&gt;
+&lt;form&gt;
+  &lt;legend&gt;Legend&lt;/legend&gt;
   &lt;label&gt;Label name&lt;/label&gt;
   &lt;input type="text" placeholder="Type something…"&gt;
   &lt;span class="help-block"&gt;Example block-level help text here.&lt;/span&gt;