Fixing old annotation @Validation references

Author: weaverryan

book/forms.rst

@@ -282,13 +282,13 @@ number:
  class Product
  {
  /**
- * @validation:NotBlank()
+ * @assert:NotBlank()
  */
  public $name;
 
  /**
- * @validation:NotBlank()
- * @validation:Min(0)
+ * @assert:NotBlank()
+ * @assert:Min(0)
  */
  protected $price;
  }