Modified example according to code changes

Author: luiru72

_tour/extractor-objects.md

@@ -45,12 +45,18 @@ val CustomerID(name) = customer2ID
 println(name)  // prints Nico
 ```
 
-This is equivalent to `val name = CustomerID.unapply(customer2ID).get`. If there is no match, a `scala.MatchError` is thrown:
+This is equivalent to `val name = CustomerID.unapply(customer2ID).get`.
 
-```tut:fail
+```tut
 val CustomerID(name2) = "--asdfasdfasdf"
 ```
 
+If there is no match, a `scala.MatchError` is thrown:
+
+```tut:fail
+val CustomerID(name3) = "-asdfasdfasdf"
+```
+
 The return type of an `unapply` should be chosen as follows:
 
 * If it is just a test, return a `Boolean`. For instance `case even()`.