Fix language tags in doc-snippets

The doc-snippets were inconsistent
(no spaces before title, small-caps, JS
instead of JavaScript, etc.)

apps/tests/ui/image/image-tests.ts

@@ -7,7 +7,7 @@ import ImageModule = require("ui/image");
 // ```
 
 // Binding the image source property to a view-model property.
-//```XML
+//``` XML
 // <Page>
 //   <StackLayout>
 //      <!--Bind the image source property to view-model property -->
@@ -276,4 +276,4 @@ export var test_SettingStretch_none = function () {
     }
 
     helper.buildUIAndRunTest(image, testFunc);
-}
+}