docs: add missing priority documentation for structural directives

Author: IgorMinar

src/ng/directive/ngIf.js

@@ -38,6 +38,7 @@
  *
  * @element ANY
  * @scope
+ * @priority 600
  * @param {expression} ngIf If the {@link guide/expression expression} is falsy then
  *     the element is removed from the DOM tree. If it is truthy a copy of the compiled
  *     eleent is added to the DOM tree.

src/ng/directive/ngInclude.js

@@ -29,6 +29,7 @@
  * The enter and leave animation occur concurrently.
  *
  * @scope
+ * @priority 400
  *
  * @param {string} ngInclude|src angular expression evaluating to URL. If the source is a string constant,
  *                 make sure you wrap it in quotes, e.g. `src="'myPartialTemplate.html'"`.

src/ng/directive/ngSwitch.js

@@ -31,6 +31,7 @@
  * </ANY>
  *
  * @scope
+ * @priority 800
  * @param {*} ngSwitch|on expression to match against <tt>ng-switch-when</tt>.
  * @paramDescription
  * On child elements add:

src/ngRoute/directive/ngView.js

@@ -23,6 +23,7 @@ ngRouteModule.directive('ngView', ngViewFactory);
  * The enter and leave animation occur concurrently.
  *
  * @scope
+ * @priority 400
  * @example
     <example module="ngViewExample" deps="angular-route.js" animations="true">
       <file name="index.html">