Revert "Fixed syntax error in "block setting of attributes" example."

Code and CHANGELOGS can't be edited in docrails.
You'll need to make this change in rails/rails.

This reverts commit 465752b.

activerecord/CHANGELOG

@@ -62,7 +62,7 @@ a URI that specifies the connection configuration.  For example:
       has_one :account
     end
 
-    user.build_account{ |a| a.credit_limit = 100.0 }
+    user.build_account{ |a| a.credit_limit => 100.0 }
 
   The block is called after the instance has been initialized. [Andrew White]