Fix indentation.

Author: guhelski

topics/about_control_structures.js

@@ -25,7 +25,7 @@ test("for in", function() {
 	var result = "";
 	// for in enumerates the property names of an object
 	for (var property_name in person) {
-  result = result + property_name;
+  		result = result + property_name;
 	};
 	equal(__, result, 'what is the value of result?');
 });