Fix @polymerBehavior annotation

Author: jklein24

iron-validatable-behavior.html

@@ -13,17 +13,16 @@
 
 <script>
 
-/*
-Use `Polymer.IronValidatableBehavior` to implement an element that validates user input.
-
-### Accessiblity
-
-Changing the `invalid` property, either manually or by calling `validate()` will update the
-`aria-invalid` attribute.
-
-@polymerBehavior
-*/
-
+  /**
+   * Use `Polymer.IronValidatableBehavior` to implement an element that validates user input.
+   *
+   * ### Accessiblity
+   *
+   * Changing the `invalid` property, either manually or by calling `validate()` will update the
+   * `aria-invalid` attribute.
+   *
+   * @polymerBehavior
+   */
   Polymer.IronValidatableBehavior = {
 
     properties: {