[forms] Fixing wrong field name

Author: weaverryan

book/forms.rst

@@ -129,8 +129,8 @@ format. Symfony2 comes with many build-in types that will be discussed shortly
 
 .. tip::
 
- Notice that the form system is smart enough to access the ``money`` field
- via the ``getMoney`` and ``setMoney`` methods. You have the option of
+ Notice that the form system is smart enough to access the ``price`` field
+ via the ``getPrice`` and ``setPrice`` methods. You have the option of
  making any property either public or adding getter and setter methods
  for it.