fix(docs): fix diagram in tutorial/step_02

Removes whitespace before image tag as it caused it to be interpreted as a code block.

Closes angular#3668

Author: Nepoxx

docs/content/tutorial/step_02.ngdoc

@@ -64,7 +64,7 @@ tag as the template.
 bindings. As opposed to evaluating constants, these expressions are referring to our application
 model, which was set up in our `PhoneListCtrl` controller.
 
-      <img class="diagram" src="img/tutorial/tutorial_02.png">
+<img class="diagram" src="img/tutorial/tutorial_02.png">
 
 
 ## Model and Controller