docs(tutorial): fix markup for tutorial_04.png diagram

Author: twil

docs/content/tutorial/step_04.ngdoc

@@ -45,7 +45,7 @@ We made the following changes to the `index.html` template:
 * First, we added a `<select>` html element named `orderProp`, so that our users can pick from the
 two provided sorting options.
 
-      <img  class="diagram" src="img/tutorial/tutorial_04.png">
+<img class="diagram" src="img/tutorial/tutorial_04.png">
 
 * We then chained the `filter` filter with {@link api/ng.filter:orderBy `orderBy`}
 filter to further process the input into the repeater. `orderBy` is a filter that takes an input