Introduced new Extended action

The new `Extended()` action is simply a shortcut to the previously introduced `includeMetadata` (87b6d1b), which will, by default, be routed from `/Sitemap/Extended` (assuming e.g. `MapDefaultControllerRoute()`).

This will output the same sitemap as was previously output, with `<PageMap>` and `<DataObject>`s representing (most) attributes and relationships for every topic. This dramatically increases the size of the XML, but provides useful metadata for any agents that might support it.

Author: JeremyCaney

OnTopic.AspNetCore.Mvc/Controllers/SitemapController.cs

@@ -120,6 +120,21 @@ public virtual ActionResult Index(bool indent = false, bool includeMetadata = fa
 
     }
 
+    /*==========================================================================================================================
+    | GET: /SITEMAP/EXTENDED
+    \-------------------------------------------------------------------------------------------------------------------------*/
+    /// <summary>
+    ///   Provides the Sitemap.org sitemap for the site, including extended metadata attributes.
+    /// </summary>
+    /// <remarks>
+    ///   Introducing the metadata makes the sitemap considerably larger. However, it also means that some agents will index the
+    ///   additional information and make it available for querying. For instance, the (now defunct) Google Custom Search Engine
+    ///   (CSE) would previously allow queries to be filtered based on metadata attributes exposed via the sitemap.
+    /// </remarks>
+    /// <param name="indent">Optionally enables indentation of XML elements in output for human readability.</param>
+    /// <returns>A Sitemap.org sitemap.</returns>
+    public virtual ActionResult Extended(bool indent = false) => Index(indent, true);
+
     /*==========================================================================================================================
     | METHOD: GENERATE SITEMAP
     \-------------------------------------------------------------------------------------------------------------------------*/